Hi,
Sometimes you faced the issue that not sending emails from some domains. Follow the below steps if you see error in exim_maillog as below.
Quote[::1]:44068 F=Test@domain.name A=dovecot_login:Test@domain.name temporarily rejected RCPT Test@gmail.com: Could not complete sender verify
Steps to resolve this issue:-
To fix this issue you need disable Sender verification option.
1. Login to WHM.
2. Go to Exim configuration editor and set Off option Sender Verification.
3. Save the configuration and restart exim service.
That's it and your issue will be fixed. :) :)