Apple mail dosen't work on Brand new mac mini pro

Oops, I would start over by resetting to factory, see What to do before you sell, give away, trade in, or recycle your Mac - Apple Support.

For the reset procedure, avoid Time Machine entirely i.e. physically disconnect the TM disk. And of course, don’t even think of Migration Assistant. Both apps are dumb old Apple bots that dole out as much pain as they ease, avoid whenever possible.

Once the Mac is setup afresh, install Apps manually and likewise with user data files (assuming you’re not iCloud savvy). Files like pdf, docx, jpegs, xlsx etc. - those files should be manually copied to external disk prior to reset.)

Then setup your mail accounts afresh and let them sync up with their servers and update. Can take a few hours but without alarming notifications etc. - just let it do what it needs to do.

The other option is to wait it out for MA finish. Use Webmail until.

Good luck!

I would help if you told us from what OS version did your TM have on it when migrating. I have migrated many Macs using TM backup and no issue with mail. If you are migrating a large mile file it may show a bar at the bottom left in mail indicating mail loading. You could also remove your account in mail and then activate again and see what happens before you start the new OS install again.

Dis you use Migration Assistant?

Did you follow the steps in Setup Assistant and Migration Assistant?

Also, do you have any of the following types of third party apps installed:

• Antivirus
• Cleaning
• Security
• VPN
• Maintenance