Can't connect from Mac Mail to Comcast email

When I enter my password for my Comcast email account, I get the reply that it can't verify the password and account. I know the password is correct, because I can connect to email from my iPhone. I know that the IMAP and SMTP fields are correct. I don't know why the connection fails. Don't tell me to change my password and try again. I've done that multiple times. The connection from my phone continues to work and the connection from my Mac continues to fail. Is there any way to get help to solve this problem?