Fixed: Ensure failing indexers are marked as failed when testing all

(cherry picked from commit b407eba61284d5fb855df6a2868805853aa6f448)

src/NzbDrone.Core/Indexers/Definitions/Newznab/Newznab.cs

@@ -25,7 +25,7 @@ namespace NzbDrone.Core.Indexers.Newznab
         public override bool SupportsPagination => true;
         public override IndexerPrivacy Privacy => IndexerPrivacy.Private;
         public override IndexerCapabilities Capabilities { get => GetCapabilitiesFromSettings(); protected set => base.Capabilities = value; }
-        public override int PageSize => _capabilitiesProvider.GetCapabilities(Settings, Definition).LimitsDefault.Value;
+        public override int PageSize => GetProviderPageSize();
 
         public override IIndexerRequestGenerator GetRequestGenerator()
         {
@@ -209,5 +209,17 @@ namespace NzbDrone.Core.Indexers.Newznab
                 return new ValidationFailure(string.Empty, "Unable to connect to indexer, check the log above the ValidationFailure for more details");
             }
         }
+
+        private int GetProviderPageSize()
+        {
+            try
+            {
+                return _capabilitiesProvider.GetCapabilities(Settings, Definition).LimitsDefault.GetValueOrDefault(100);
+            }
+            catch
+            {
+                return 100;
+            }
+        }
     }
 }