Dear EJ90s,
Good day! Thank you for posting to Microsoft Community. I am happy to help you.
According to your description, I understand that I sent a re-upload file.
You can try switching between browsers to see if you can upload the file. If this problem occurs in multiple browsers, there is a problem on the server side while the application is running.
In this situation, I am sorry and recommend you to connect with the related development team where they can check the internal sources and investigate the issue further.
So, I request you to connect with your IT admin of your organization (How do I find my Microsoft 365 admin? - Microsoft Support) and ask them to raise a new service request from the Microsoft 365 admin center so that the related development team will connect with you and investigate the issue further.
Reference: Get support - Microsoft 365 admin | Microsoft Learn
Note: I apologize for redirecting you to related development support team because the moderators in this community are limited with the resource for further investigation and to get a quick resolution to your problem, I requested it.
Thanks for your cooperation.
Sincerely,
Tin | Microsoft Community Moderator