Enter your name, email address, password and click ‘Continue’.

Now click ‘Configure manually’

Enter these settings:
Incoming server:-
Protocol: IMAP
Hostname: mail.<yourdomain>
Port: 143
Connection security: STARTTLS
Authentication method: Normal password
Username: <username>

Outgoing server:-
Hostname: mail.<yourdomain>
Port: 587
Connection security: STARTTLS
Authentication method: Normal password
Username: <username>

Then click on ‘Re-test’.

Then click on ‘Done’