This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice This article is not considered official documentation for K2 software and is provided "as is" with no warranties.

Issue

When you have a solution that is created from a Sharepoint list and you choose to create a workflow which should start once a list item is added, it fails to work. The workflow still works if started manually.

This happens with legacy workflows that were created on 4.6.11 and earlier versions.

Symptoms

You will notice an error within the hostserver log file which can be seen within the following location:
Program Files x 86 > K2 Blackpearl > Host Server > Bin, outlining the following:

"Error","IdentityService","64018","SharePointGroupProviderResolveNameException", "SPCsomClient.GetUser","64018 Failed to resolve user 'i:0i.t|00000003-0000-0ff1-ce00-000000000000|app@sharepoint' on SharePoint site 'https://###.sharepoint.com/sites/***',

Error: System.Reflection.TargetInvocationException: An unexpected failure was encountered when contacting SharePoint to get information from the group provider CSR: Key cannot be null. Parameter name: key ---> System.ArgumentNullException: Key cannot be null"

Troubleshooting Steps

To resolve this issue please follow the instructions within the KB article below which would require a direct modification within the hostserver.exe.config file. This should be in the same location as the host server log file as mentioned above:
http://help.k2.com/kb002929

The workflow should start automatically again as expected.