Hi, I'm using a Droplet with a single domain since a year now and it has a mail server configured as well (iRedmail).
Everything works perfectly but now I need to add a new domain for mailing so how can I do that?

Things which I have already done-

1. I have changed the new domain's nameservers.
2. Added the new domain in the Domains section via Digital Ocean's Dashboard.
3. Added a new domain on iredmail admin panel and created new email accounts.

Now when I login using the new email accounts, it all works well but emails are not being delivered.

Please help.