MTA quits connection

Dear Community,

recently I noticed that some emails do not get delivered to the recipient. I did not find any error in the logs, email cue is empty.The admin support on the other end notice a “[smptp] closed by quit”. I am quite shure that this is not a nethserver problem.

  • I have this problem only with one service supplier - if it would be nethserver, I should have more problems

On the other hand, the error on the other side “[smptp] closed by quit” points to nethserver:

  • All I find on google about this error is related to rsampd / exim ?
  • It seems to be a time-out?

Log files on the recipent side:
2021-03-04 10:17:28 SMTP connection from mail.xyz.tld (ebb-s01.xyz.tld) [80.254.xxx.xxx]:39866 I=[168.119.43.205]:25 closed by QUIT

2021-03-04 13:07:30 SMTP connection from mail.v (ebb-s01.xyz.tld) [80.254.xxx.xxx]:54740 I=[168.119.43.205]:25 closed by QUIT

2021-03-04 13:15:59 SMTP connection from mail.xyz.tld (ebb-s01.xyz.tld) [80.254.xxx.xxx]:55430 I=[168.119.43.205]:25 closed by QUIT

2021-03-04 13:18:16 SMTP connection from mail.xyz.tld (ebb-s01xyz.tld) [80.254.xxx.xxx]:55534 I=[168.119.43.205]:25 closed by QUIT

NethServer Version: 7.9.2009
Module: email : dovecot / postfix / rspamd (exim?)