Welcome to Justanswer.com, my name is ***** ***** I will do my best to0 assist you.
To get started, can you send a reply including the mac osx version you have. Here is how to check.
Click the apple sign at the top left of your screen, then click about this mac. And then where it says version, send that to me as a reply.
Also, the email account thats not working on mac mail, what type of email account is it. Gmail, AOL, Yahoo, etc ?
Thank you for your response,
Dustin S.Senior Technician and Network Switching Systems Operator / Maintainer.
Is it possible you have keyboard issues? Does your mac have a guest account or any other accounts that you can sign into ?