Critical issue

Getting bad request when trying to save any .pbix to report server via pbi desktop or through portal via upload file.

Both are running 2021 on prem. 

Error from desktop is: Error occured while attempting to save report to server

Error from portal\upload: There was an error uploading your .pbix file. Verify that the file had not been corrupted and the the file extension matches the format of the file

Have tried:

- many different .pbix

- repair install of the client

- repair install of the server

- fresh server install

- New database (2014 SQLServer)

- New database on a different server (2017 SQLServer)

- moving a pbix within the server via portal\move works fine

- exisiting reports work fine

Any thoughts would be appreciated,

Thanks

Logs:

2021-03-12 20:48:26.7967|ERROR|11|library|Throwing Microsoft.ReportingServices.Diagnostics.Utilities.ItemNotFoundException: , Microsoft.ReportingServices.Diagnostics.Utilities.ItemNotFoundException: The item '/xxxxx' cannot be found.;| RequestID = s_cdb60e03
2021-03-12 20:48:28.1248|ERROR|8|The remote server returned an error: (400) Bad Request.| RequestID = s_cdb60e03