diff --git a/backend/src/main/resources/dynamic-http-metadata-provider.schema.json b/backend/src/main/resources/dynamic-http-metadata-provider.schema.json
index b63277580..8be8bbf9b 100644
--- a/backend/src/main/resources/dynamic-http-metadata-provider.schema.json
+++ b/backend/src/main/resources/dynamic-http-metadata-provider.schema.json
@@ -122,7 +122,7 @@
                                     "title": "label.background-init-from-cache-delay",
                                     "description": "tooltip.background-init-from-cache-delay",
                                     "type": "string",
-                                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                                 }
                             }
                         },
@@ -149,19 +149,19 @@
                     "title": "label.min-cache-duration",
                     "description": "tooltip.min-cache-duration",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxCacheDuration": {
                     "title": "label.max-cache-duration",
                     "description": "tooltip.max-cache-duration",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxIdleEntityData": {
                     "title": "label.max-idle-entity-data",
                     "description": "tooltip.max-idle-entity-data",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "removeIdleEntityData": {
                     "title": "label.remove-idle-entity-data",
@@ -172,7 +172,7 @@
                     "title": "label.cleanup-task-interval",
                     "description": "tooltip.cleanup-task-interval",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "persistentCacheManagerDirectory": {
                     "title": "label.persistent-cache-manager-directory",
@@ -271,7 +271,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "connectionTimeout": {
                     "type": "string",
@@ -291,7 +291,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "socketTimeout": {
                     "type": "string",
@@ -311,7 +311,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "tlsTrustEngineRef": {
                     "type": "string",
diff --git a/backend/src/main/resources/file-system-metadata-provider.schema.json b/backend/src/main/resources/file-system-metadata-provider.schema.json
index f2ce9e7c3..d238018b9 100644
--- a/backend/src/main/resources/file-system-metadata-provider.schema.json
+++ b/backend/src/main/resources/file-system-metadata-provider.schema.json
@@ -52,13 +52,13 @@
                     "title": "label.min-refresh-delay",
                     "description": "tooltip.min-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxRefreshDelay": {
                     "title": "label.max-refresh-delay",
                     "description": "tooltip.max-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "refreshDelayFactor": {
                     "title": "label.refresh-delay-factor",
diff --git a/backend/src/main/resources/filebacked-http-metadata-provider.schema.json b/backend/src/main/resources/filebacked-http-metadata-provider.schema.json
index 655ff5e0d..9ce22ca94 100644
--- a/backend/src/main/resources/filebacked-http-metadata-provider.schema.json
+++ b/backend/src/main/resources/filebacked-http-metadata-provider.schema.json
@@ -130,7 +130,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "connectionTimeout": {
                     "type": "string",
@@ -150,7 +150,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "socketTimeout": {
                     "type": "string",
@@ -170,7 +170,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "tlsTrustEngineRef": {
                     "type": "string",
@@ -257,13 +257,13 @@
                     "title": "label.min-refresh-delay",
                     "description": "tooltip.min-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxRefreshDelay": {
                     "title": "label.max-refresh-delay",
                     "description": "tooltip.max-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "refreshDelayFactor": {
                     "title": "label.refresh-delay-factor",
@@ -297,7 +297,7 @@
                             "title": "label.max-validity-interval",
                             "description": "tooltip.max-validity-interval",
                             "type": "string",
-                            "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                            "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                         }
                     }
                 },
diff --git a/backend/src/main/resources/local-dynamic-metadata-provider.schema.json b/backend/src/main/resources/local-dynamic-metadata-provider.schema.json
index 07fcf7674..1b1951dac 100644
--- a/backend/src/main/resources/local-dynamic-metadata-provider.schema.json
+++ b/backend/src/main/resources/local-dynamic-metadata-provider.schema.json
@@ -55,19 +55,19 @@
                     "title": "label.min-cache-duration",
                     "description": "tooltip.min-cache-duration",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxCacheDuration": {
                     "title": "label.max-cache-duration",
                     "description": "tooltip.max-cache-duration",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxIdleEntityData": {
                     "title": "label.max-idle-entity-data",
                     "description": "tooltip.max-idle-entity-data",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "removeIdleEntityData": {
                     "title": "label.remove-idle-entity-data",
@@ -78,7 +78,7 @@
                     "title": "label.cleanup-task-interval",
                     "description": "tooltip.cleanup-task-interval",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 }
             }
         }
diff --git a/ui/public/assets/schema/provider/filebacked-http.schema.json b/ui/public/assets/schema/provider/filebacked-http.schema.json
index 2a2783843..860733486 100644
--- a/ui/public/assets/schema/provider/filebacked-http.schema.json
+++ b/ui/public/assets/schema/provider/filebacked-http.schema.json
@@ -130,7 +130,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "connectionTimeout": {
                     "type": "string",
@@ -150,7 +150,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "socketTimeout": {
                     "type": "string",
@@ -170,7 +170,7 @@
                             "PT24H"
                         ]
                     },
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "tlsTrustEngineRef": {
                     "type": "string",
@@ -257,13 +257,13 @@
                     "title": "label.min-refresh-delay",
                     "description": "tooltip.min-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "maxRefreshDelay": {
                     "title": "label.max-refresh-delay",
                     "description": "tooltip.max-refresh-delay",
                     "type": "string",
-                    "pattern": "^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
+                    "pattern": "^$|^(R\\d*\\/)?P(?:\\d+(?:\\.\\d+)?Y)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?W)?(?:\\d+(?:\\.\\d+)?D)?(?:T(?:\\d+(?:\\.\\d+)?H)?(?:\\d+(?:\\.\\d+)?M)?(?:\\d+(?:\\.\\d+)?S)?)?$"
                 },
                 "refreshDelayFactor": {
                     "title": "label.refresh-delay-factor",