https://gitlab.synchro.net/main/sbbs/-/commit/52099548d7f5782b818bdbe7
Modified Files:
src/sbbs3/mailsrvr.cpp
Log Message:
mailsrvr: POP3 reply -ERR (not !UNSUPPORTED) to USER/PASS in TRANSACTION state

Some clients (e.g. Thunderbird) reuse an already-authenticated TCP socket
and re-issue USER/PASS. Per RFC 1939 these are AUTHORIZATION-state-only commands, so respond with a plain -ERR and keep the session alive,
matching Dovecot/Courier behavior and suppressing the misleading
"!UNSUPPORTED COMMAND" log notice.

Refs main/sbbs#1123

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
--- SBBSecho 3.37-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)