Email alias not found despite being in directory

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I have set up three email aliases via the Stalwart 16.6 Admin UI. Two out of the three work. The last one says; 550 5.1.2 Mailbox does not exist when I test it with Swaks. I’ve removed it and re-added it via the UI but nothing seems to work. How can this be fixed?

I understand that topics in this category are triaged by a bot first but a human reply will follow up. If I’d prefer a human-only reply, I’ll add the no-ai tag to my topic.

on

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Since your other two aliases deliver fine, the general setup is right and it’s something specific to that one address. The 550 5.1.2 means that exact address isn’t resolving to an enabled recipient on a local domain. A few things that would cause it for just one alias: the alias is disabled on the account; a typo, a trailing space, or a different (non-local) domain in that entry; it’s already used somewhere else as a primary or alias (addresses have to be unique, and a collision won’t attach to the intended account); or it contains a + and the domain has sub-addressing enabled, in which case everything after the + is stripped before lookup.

3

Thanks for the reply.

I ended up restarting stalwart via systemd and the alias worked. I had tried a number of things before that, like deleting and re-entering the email address, checking whitespace, etc. I’m not sure what was the exact change I made but it likely was one of the ones you mentioned.