You may experience this error in the Revit addin:
You can use Deep Space dashboards to diagnose the problem.
For example, an identical BIM360 file name may be present, and appear like this:
If you have loaded BIM360 file data to Deep Space, you can observe these duplicates in our File Name Audit dashboards:
In Revit, it may be advisable to Unload the duplicate link from your Federated Model and re-checking the Revit addin Configuration. Is the Duplicate link now gone?
You may be able to rectify long term by deleting the duplicate file on BIM360:
Then proceed to Reconfigure the files using the Revit addin.