"Mail account already exists" error when trying to send/recieve email

pennyeG wrote:

My MacBook Pro stopped receiving emails and wouldn't let me send either. When I tried to get emails it prompts me to enter the password for the account. When I enter the password an error message pops up "account already exists". How can I get Mail to work?

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