Thank you for posting this in Microsoft Q&A.
I understand you are trying to bulk enable per-user MFA through the Office 365 Admin portal or the Entra ID Admin portal, but it fails with "Correlation ID e1fc7f1d-a480-44c3-b694-147f7ed78c91" and "ERROR CODE: 0".
The "Error Code 0" message is a generic error message that indicates that the operation failed, but the reason for the failure is not known. Here are some troubleshooting steps that you can try:
1.Check the format of the CSV file: Verify that the CSV file is in the correct format and matches the template given by Microsoft. The CSV file has columns for Username and MFA status.
2.Try logging in to the Microsoft Entra admin center using a different browser and attempting to utilize the bulk update option.
Hope this helps. Do let us know if you any further queries.