Am Samstag, dem 06.04.2024 um 14:34 +0000 schrieb lua8ds--- via dovecot:
My current setting was not the default; I had: auth_username_format = %n
So I updated that setting to: auth_username_format = %Lu expecting that %Lu would lowercase the username - and that my problem would be fixed.
It does not though. Updating this setting not only prompts my email server to still reject USERNAME@redacted.com, but now also rejects (lowercase username) username@redacted.com (which my server had no issue receiving beforehand).
So I reverted auth_username_format to: auth_username_format = %n
Emails sent to username@redacted.com land in my mailbox again - but emails sent to USERNAME@redacted.com still don't.
What can I try to troubleshoot? Which config file shall I share with you?
Try %Ln. It should work for you.