Bug Report: Pocket ID seems to be sending malformated SMTP commands, triggering firewall blocks

Reproduction steps

Hello!

I don't know exactly how to reproduce this. I am just using Pocket ID normally, with a "private" (small company) SMTP server (which might be the problem…) The SMTP server is behind a cPanel, I believe, and it's an EXIM, I think.

Expected behavior

Pocket ID doesn't trigger any firewall filters.

Actual Behavior

Pocket ID seems to be sending weird SMTP command such as this:

LOG:
lfd[116423]: (eximsyntax) Exim syntax errors from ~~redacted_ip~~ (DE/Germany/vmi3278709.~~redacted_host~~): 10 in the last 3600 secs - *Blocked in csf* [LF_EXIMSYNTAX]

2026-05-18 20:58:45 SMTP call from vmi3278709.~~redacted_host~~ [~~redacted_ip~~]:39166 dropped: too many syntax or protocol errors (last command was "\b\v\b\004\b\005\b\006\004\001\005\001\006\001\003\003\003\001\003\002\004\002\005\002\006\002?+?\005\004\003\004\003\003?-?\002\001\001?3\004\352\004\350\021\354\004\300^\002\242\213\361eO\vK\242\204\020\030", NULL)
2026-05-18 20:59:46 SMTP connection from [~~redacted_ip~~]:50798 (TCP/IP connection count = 2)

Pocket ID Version

v2.7.0

Database

SQLite

OS and Environment

Docker (in compose) on Ubuntu

Log Output

After we're blocked, we cannot connect to the SMTP server anymore:

May 20 18:53:55 ERR Request with errors: Error #01: failed to connect to SMTP server: failed to connect to SMTP server: dial tcp ~~redacted_ip~~:587: i/o timeout