https://gitlab.synchro.net/main/sbbs/-/issues/1123#note_8804
The USER and PASS commands end up logged as unsupported commands and rejected by the server:
```
4/15 12:03:46a 9476 POP3 <User Name> !UNSUPPORTED COMMAND: 'USER user name'
4/15 12:03:46a 9476 POP3 <User Name> !UNSUPPORTED COMMAND: 'PASS secret' ```
Once authenticated, these commands are rejected by the mail server and that can confuse ThunderBird as it sometimes reuses the same already-connected TCP socket to get new mail and attempt to authenticate a second time.
--- SBBSecho 3.37-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)