Gmail in the mail app not working

If the automatic setup for your GMail account isn't working, adding it manually may work. T-Mobile helpfully provides step-by-step instructions here:

https://www.t-mobile.com/support/tutorials/device/apple/iphone-13/topic/email-amp-messaging/manual-configuration/choice/gmail

Hope that works.

Regards.

1. Open Apple Mail on your computer.
2. Click Mail > Add Account.
3. Select the Google option, then click Continue:
4. If prompted, click Open Safari to let Google to finish authentication:
5. Enter your Google Gmail email address in the Google Sign in window and click Next:
6. Enter your password in the Google Welcome window and click Next. If prompted, select Allow to grant permissions to your account.
7. Check the mailbox to select the apps you want to use with this account.
8. Click Done.