unable to send email from MacBook Air

Hello, I have a macbook Air w/ Catalina that will not send or receive email. It appears to think I should sign in w/ a password on an account I deleted two years ago.

Oddly, I am able to receive and send from other Apple devices.

Friday I spent a few hours on this problem updating from Mojave to Catalina, but the email still does not send.

I'm fearful of deleting my accounts on this device since I'm unsure if it will mess up my other devices...

Can anyone help?