Apple Mail Version 13.4 (3608.120.23.2.4)

Hello John,

We are here to address your concern with Mail. It seems you can receive mail and sending mail is the issue. We'll look into this with the steps below:

If you can’t send or receive email on your Mac try these steps first.

If iCloud Mail isn't working these steps will apply.

Cheers.

Hello John,

Good job working with those steps already. Since the connection works temporarily after a restart try safe mode.

Start up your Mac in safe mode with the steps here.

Let us know if this works while in safe mode, or after restarting and booting regular after testing.

Cheers.

Hello John,

Thanks for replying. Check out the information below, from the resource titled If iCloud Mail isn't working:

"Your ISP might be blocking the protocol used to send email (SMTP) across their network. Contact your service provider and ask about SMTP traffic that crosses their network to an external service, such as iCloud. If your service provider blocks SMTP traffic, ask them how you can be exempted from SMTP blocking."

Contact Apple Support for further support.

We hope this helps.