Overview:
Collaborative authoring connects Vault to Office 365™ to allow multiple users to edit a document at the same time using the Office desktop software, Office Online™, the Office mobile apps, or in a browser. When the user tries to click on the 'Edit in Microsoft office' option to do collaborative authoring gets the error as attached.
Root Cause:
The document is manually deleted by someone that's not a Vault Collaboration which goes against how the Collaborative Authoring process is supposed to work.
Solution:
To check who deleted the document in Sharepoint, the admins can go to the Recycling Bin and see:
In regards to restoring an item from the Recycling Bin, here's an article for that:
Restore items in the recycle bin that were deleted from SharePoint or Teams
Related Documentation:
Microsoft Articles :