C2C agent tries to apply a protection plan to O365 mailboxes, Sharepoint, etc.
Activity fails with:
A backup agent error: 'nothing is processed in protection applying'
The alert could appear if there are new resources but they weren't protected when applying the plan, for example when there are new items discovered in Microsoft 365.
To synchronize the changes between Microsoft 365 and Acronis console follow this article
The resource has a long name; it's not possible to protect the site if it's name exceed the maximum length. The current limitation is 186 characters.
In this case, change the name of resources from Microsoft 365 side.