2017-05-31 18:07:59 [28538] SMTP connection from <snip> :18105 I=:25 lost while reading message data
2017-05-31 18:07:59 [28538] SSL_write: (from <snip>:18105) syscall: Broken pipe
We find from one host this in the logfiles. Spend a day trying, googling etc etc. And whatever i try, no solution...