After installing Mail Server on a fresh VPS, it fills up MySQL error log

aaP_bencusix

2026-03-02 16:52:53 16649 [Warning] Aborted connection 16649 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:52:53 16650 [Warning] Aborted connection 16650 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:03 16651 [Warning] Aborted connection 16651 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:03 16652 [Warning] Aborted connection 16652 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:13 16653 [Warning] Aborted connection 16653 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:13 16654 [Warning] Aborted connection 16654 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:23 16655 [Warning] Aborted connection 16655 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:23 16656 [Warning] Aborted connection 16656 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:33 16657 [Warning] Aborted connection 16657 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:33 16658 [Warning] Aborted connection 16658 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:43 16659 [Warning] Aborted connection 16659 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:43 16660 [Warning] Aborted connection 16660 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:50 16661 [Warning] Aborted connection 16661 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:53:50 16662 [Warning] Aborted connection 16662 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:54:00 16663 [Warning] Aborted connection 16663 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-02 16:54:00 16664 [Warning] Aborted connection 16664 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)

Can anyone help me with this? I tried ChatGPT, but it cannot find the issue

aaPanel_Kern

aaP_bencusix
Hello,
Please check if others can connect to your mysql port from outside?

aaP_davide2

Same problem here versione 8.0.1

tons of and my server hang after 24/48 hours

6-03-31 22:27:37 6548 [Warning] Aborted connection 6548 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:27:47 6550 [Warning] Aborted connection 6550 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:27:57 6551 [Warning] Aborted connection 6551 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:07 6555 [Warning] Aborted connection 6555 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:17 6557 [Warning] Aborted connection 6557 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:27 6560 [Warning] Aborted connection 6560 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:37 6561 [Warning] Aborted connection 6561 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:47 6562 [Warning] Aborted connection 6562 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:28:57 6570 [Warning] Aborted connection 6570 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:07 6579 [Warning] Aborted connection 6579 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:17 6585 [Warning] Aborted connection 6585 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:27 6587 [Warning] Aborted connection 6587 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:37 6588 [Warning] Aborted connection 6588 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:47 6589 [Warning] Aborted connection 6589 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:29:57 6592 [Warning] Aborted connection 6592 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:30:07 6598 [Warning] Aborted connection 6598 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:30:17 6599 [Warning] Aborted connection 6599 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:30:27 6600 [Warning] Aborted connection 6600 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)
2026-03-31 22:30:37 6601 [Warning] Aborted connection 6601 to db: 'unconnected' user: 'unauthenticated' host: 'localhost' (This connection closed normally without authentication)

aaPanel_Kern

Hello,
This error does not affect
It is recommended that you set the log level
add log_warnings = 1 in the Config file first
Then restart mysql

aaP_davide2

aaP_zayanhani34

Look

Since it is coming from localhost and showing unauthenticated, it doesn't look like an external attack more likely one of the mail components trying to connect every few seconds.

You might want to check:

Mail server services (Postfix, Dovecot, etc.)
Webmail (Roundcube / RainLoop if installed)
Cron jobs or monitoring scripts
Database credentials in mail server config files