If you experience the error after publishing a new application or customizing an application’s icon, check the event viewer on the StoreFront server and look for the following errors:
Event 1 = There was an error during a resources List request. System.Net.WebException, System, Version=220.127.116.11, Culture=neutral, PublicKeyToken=b77a5c561934e089
The remote server returned an error: (500) Internal Server Error.
Event 7 = Unhandled exception thrown for route “DazzleResources/List” System.ArgumentException, mscorlib, Version=18.104.22.168, Culture=neutral, PublicKeyToken=b77a5c561934e089 Offset and length were out of bounds for the array or count is greater than the number of elements from index to the end of the source collection.
The workaround is to go to Studio > Delivery Groups > Applications > view the properties of the application recently added > Delivery > Application Icon > Change and choose from any of the Citrix default icons.