4macmare wrote:
I have changed port, checked "use TLS/SSL, and authentication- Password" (instructions given by server.) I click "save" however, settings returns to the wrong settings. Can't send anything out. Do receive messages from this server.
with no details my best advise—
For problem accounts the go to way to sort things out is to delete the account(s) from the Mail.app, then add it back.
Remove email accounts in Mail on Mac
Remove email accounts in Mail on Mac - Apple Support
Add email accounts in Mail on Mac - Apple Support
Add email accounts in Mail on Mac - Apple Support
Note—
IMAP accounts stay on the server, so no local loss, when you re-sync
POP accounts download and remove from the server—therefor save your inbox/sent box if you want them
“On My Mac" is just that, local folders you created and moved mail into. So no loss