G Suite email - Recipient address rejected: User unknown in virtual mailbox table

[eifersucht]

I’ve configured several domains in the admin panel, But one of this domains is configured to use mail-in-a-box for dns administration and handle the email accounts from G Suite (I’ve override MX with google MX reg. ).

But when I’m going to send an email from one of my mail-in-a-box hosted accounts to one of this G Suite emails, I’m getting " Recipient address rejected: User unknown in virtual mailbox table" error.

My hosted account is an alias managed from gmail.

email1@domain1.com (configured as an alias in mail-in-a-box)

to

email2@domain2.com (Configured in G suite using googles MX in mail-in-a-box)

I need help.

Thank you.

[murgero]

You can ONLY login to MIAB SMTP server with an actual user, not an ALIAS, however, when sending an email you can change the “FROM” address to any alias configured for the username as long as you are authenticated…