DataFormWebPart may be blocked from accessing an external URL, and it generates "8scdc" event tags in SharePoint Unified Logging System (ULS) logs.
Because of security concerns, DataFormWebPart was changed to support only accessing internal URLs.
To work around this issue, you can contact the farm administrator to use PowerShell to add the blocked host name to SPFarm.AllowedSafeDomain.
For example, assume that you find the following message in the ULS logs:
8scdc http://externalURL url not allowed in ResloveUri, you can contact farm admin to add the host name to SPFarm.AllowedSafeDomain
Open PowerShell, and run the following cmdlets: