Postfix rejects external emails to alias after user deletion

[lucagasparini]

After deleting a user whose built-in address was configured as internal, and then creating an alias pointing that same address to another account, Postfix permanently rejects all incoming external emails to that alias.

Steps to reproduce

• Create user1 in NethServer 8
• Set user1@domain.tld built-in address as internal
• Delete user1
• Create a new alias user1@domain.tld pointing to another existing account
• Send an external email to user1@domain.tld

Expected behavior

Postfix should accept the incoming email and deliver it to the target account defined in the alias.

Actual behavior

Postfix rejects all incoming external emails to the address user1@domain.tld with a permanent rejection error, despite the alias being configured correctly.
The log reports:

554 5.7.1 <user1@dominio>: Recipient address rejected: access denied;

Components

ns8-mail

See also

Discussion: https://mattermost.nethesis.it/nethesis/pl/feno1od5wifd9ka6dtjmsauwdw