In the Enterprise Vault http log we see below error message:
14/06/2021 15:17:57 [7988,37] - Fetching item content from vault
14/06/2021 15:17:57 [7988,37] - ** Error: msgSym = GenericError
14/06/2021 15:17:57 [7988,37] - ** Error: msg = Error calling ECMOperations.GetVaultItem: Cannot complete the operation.
Additional support information:
Security Access Denied. Check the application pool account access permissions on the Claims to Windows Token service on the SharePoint server.
14/06/2021 15:17:57 [7988,37] - ** Error: exCode = 0
As mentioned in the below Microsoft article the Claims to Windows Token Service (C2WTS) should be configured under domain user account and permissions need to be assigned in Local Security Policy.
MS Article: http://support.microsoft.com/kb/2722087
Ensure the account is a part of the Local Administrators Group and grant the C2WTS account the following permissions in the local security policy under Local Policies > User Rights Assignment:
For more information on EV SharePoint logging please refer to the Related articles section.