Database entries not getting deleted

Hi all,

I think i found a problem with the current version where entries in the database are not getting removed. I found this problem when testing and trying to use the same name and shortname when creating a new mail server in the UI.

## To Reproduce

1. Create a new mail server under "(Organisation name)→ Build a new mail server" with name test & id 577 (Doesn't matter which name & ID)
2. Delete the mail server under "Settings -> delete -> Delete this mail server and all messages"
3. Create the mail server again with the same name & id

I then got the following error:

When you look in the database under the postal database in the servers table you see the following:
It is not only the servers table, there are also still refrences in the domains table and likely many more.