Hi
If you log into your server via SSH you can run the following commands. This will show whether the mail service is activated on the domain:
/usr/local/psa/bin/domain -i domain.example.com | grep “Mail service”
This will turn off the mail service for the subdomain (Using true instead of false will turn it back on):
/usr/local/psa/bin/domain -u domain.example.com -mail_service false
Thank you,