Emails forwarded to Service Desk email don't come

Summary

When I send emails directly to the email address provided on the Settings page, issues are created.

But when I forward them from external email using postfix, issues don't appear.

Steps to reproduce

Use your postfix with forwarding config.

What is the current bug behavior?

Emails don't come.

What is the expected correct behavior?

Emails should come.

Relevant logs and/or screenshots

Apr 24 00:13:14 host1 postfix/smtp[24350]: 2C03D38DF1: to=<incoming+ulrith/Plan-and-do@gitlab.com>, orig_to=<support@plan-and-do.com>, relay=aspmx.l.google.com[209.85.200.26]:25, delay=0.76, delays=0.02/0.01/0.39/0.35, dsn=2.0.0, status=sent (250 2.0.0 OK 1492981994 s190si9038340itb.13 - gsmtp)
Apr 24 00:13:14 host1 postfix/qmgr[23347]: 2C03D38DF1: removed

Output of checks

This bug happens on GitLab.com