DNN Evoq 9.1.1 Error: A critical error has occurred


In some situations, users might encounter a critical error message when accessing their site. Critical error messages may also be present when viewing the content visualizers.



  • Access to a Superuser account.
  • (In step 3) Access to site root directory and files
  • (In step 3) Access to SQL server



If you browse to the DNN log files, you will see the following error:

System.IndexOutOfRangeException: Index was outside the bounds of the array.  at System.Collections.Generic.List`1.Contains(T item)  at DotNetNuke.Entities.Urls.CustomUrlDictController.FetchCustomUrlDictionary(Int32 portalId, Boolean forceRebuild, Boolean bypassCache, FriendlyUrlSettings settings, SharedDictionary`2& customAliasForTabs, Guid parentTraceId)



There are three possible fixes to this error which should be attempted in order. If the first doesn't fix it, the second should be tried, etc. Each subsequent fix is more technically demanding and works with more fundamental site data, and so has additional precautions that should be taken. Be sure to test after each fix.

The fixes, in order, are:

  1. Clearing the server cache. After clearing the cache, the dictionary in the memory will be updated.
  2. Content reindexing
  3. Full search reindexing

Note: This error might reoccur since it is a reported bug in Evoq 9.1.1

To permanently resolve this issue, upgrade your environment to Evoq 9.2 or later, which is documented in the defect ticket: DNN-8067.



Browsing to the page in question should no longer result in a critical error. Browser cache may need to be cleared or a hard refresh performed.



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