Mail will not send iCloud Mail

Hello. I just set up my new MacBook, and Mail will not send mail through the iCloud server. I have inserted the output below. It will send through any other email server I have, Google, Yahoo, Hotmail, etc but I can not figure out how to get iCloud mail to send. Do I need to set up the outgoing SMTP server with an app-specific password? I've never had to do that in Mail before.

Can not message using the server iCloud

Verify that you have addressed this message correctly. Check your SMTP server settings in Mail preferences and verify any advanced settings with your system administrator.

The server response was: <unknown[75.143.197.223]>: Client host rejected: Access denied

Select a different outgoing mail server from the list below or click Try Later to leave the message in your Outbox until it can be sent.

iCloud: Set up an iCloud Mail email address - Apple Support

Get help using iCloud Mail - Apple Support

Mail server settings for iCloud email clients - Apple Support

Donnutt wrote:

Ok, I was able to fix it by turning Mail off in iCloud settings, restarting Mail, and then turning it back on/rebooting Mail again.

Good computing Donnutt