Unable to import APEX Application including backup files

Summary: I have a newly created OCI account for our school and I cannot import an APEX application from a different workspace.

Content (please ensure you mask any confidential information): Here is the error message during the Import/Installation process. I cannot understand why there is an error on a fresh apex workspace from OCI.

• I have tried the solution from similar situations here but unfortunately none of them works including choosing a working backup from Applicationxx>Utilties>Manage Backups - none of them work - all end up with the same error.

Please advise, thank you in advance.

Bad Request