Template References to offline SharePoint On-Prem Server

When documents created from old .dotx templates try to load in SharePoint Online, they still contain an internal reference to the original SharePoint 2016 template library. Since the on-prem server is offline, Office applications attempt to resolve the template path, fail with a 404, and then open the document normally. The delay happens during that lookup process.

This behavior is expected because the template metadata is stored inside the file. Taking the server offline does not remove that reference.

The two practical approaches are:

• Replace the template reference by opening each template, attaching a new template, saving, and re-publishing it. New documents created from that template will no longer point to the offline server.
• Identify affected documents by scanning for URLs in the document properties or by using Office’s “File > Info > Related Documents” metadata. Files that contain embedded template paths pointing to the old SP2016 server will show this delay.

There is no automatic migration mechanism that strips old template URLs, so cleanup must be done either on the templates or by bulk document processing.