Hi,
the certificate that you have is only for your website but looking at the domains that you have tried looks like you want to check the email services ssl setting.
The best practice for this is to get a multiple domains certificate or wildcard from lets encrypt (wildcard requires DNS authentication) and use the new certificate for both web and mail services.
Contact me if you have any questions, and i will be happy to consult you or work on this ASAP.
Best Regards,
Arash