Mail to external mail service is bounced locally on Plesk server: This address no longer accepts mail

Symptoms

• When an option "bounce with message" is selected at domain mail settings, and the option "Hide bounce controls" is enabled at server settings, emails are bounced automatically even if the mail service for this domain is disabled.
• A similar error could be found at /var/log/maillog:

Sep  1 09:39:25 ns1 postfix/local[2111]: 35B87290F8: to=<_plesk_bounce_test.tld@localhost.localdomain>, orig_to=<user@test.tld>, relay=local, delay=0.04, delays=0.01/0.01/0/0.02, dsn=5.2.1, status=bounced (This address no longer accepts mail. )

Cause

This behavior is caused by a product defect with ID #PPPM-13702 -  If the option "bounce with message" is selected at domain mail settings and if "Hide bounce controls" is enabled at server settings, emails are bounced automatically, even if the mail service is disabled. It should be fixed in future Plesk Updates.

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Resolution

Disable "Hide bounce controls" an Interface management and activate/deactivate mail service for domain.

1. Login to Plesk.

2. Navigate to  Plesk > Tools & Settings > Interface Management > Interface Controls Visibility
3. Enable "Hide controls for rejection messages for non-existent mail addresses"

4. Activate/Deactivate mail service for domain.