One droplet, One Vesta, Multi domain and mail servers settings

It’s been almost two weeks that i kept failing to configure mail server.

I have one droplet with name,let’s say ‘mydroplet’, 1Gb Ram, 30Gb SSD and Ubuntu 12.04.5 x32 and successfully installed Vesta there I have successfully put several domains and sub-domains there and manage to bring the transferred website alive again (they were on shared hosting previously)

The only thing i failed is making the mail to work

I have configured the DNS on digital ocean with MX record For example, for mydomain1.com, i put 10 mail.mydomain1.com, for mydomain2.com i put 10 mail.mydomain2.com .

I still don’t know how to configure the MX records for the subdmomain (for example for sub.mydomain1.com, should i put it as 10 mail.sub.mydomain1.com(??) ? )

I can add the email address in vesta and access it through roundcube. I can even send email from there to my gmail accounts but i can’t receive any.

For additional info, my old hosting is still alive and i can still open the old email squirell through its IP (xxx.xx.xxx.xxx:2095) but i found no new or recently received email there also.

Its been almost 2 weeks…and i think i’m almost desperate…any suggestion and help?