If you want to use SMB or SharePoint Data Sources, you must configure the Active Directory account to permit Kerberos delegation to each of your SMB and SharePoint data sources.
For network shares and SharePoint servers, do the following:
Following these steps, you will enable delegation from the Gateway server to the target server(s).
Note: If you are running the Gateway server under a User account, select that User object instead.
These delegation changes, can take a few minutes to propagate depending on the size of the domain forest. You may need to wait up to 15 minutes (possibly more) for the changes to take effect. If it's still not working after 15 minutes, try restarting the Files Advanced Gateway service.