День добрый ситуация такая есть почтовый сервер на exime все прекрасно работает, но от одного поставщика письма не доходили, возник спор они утверждают, что ошибка у нас, я говорю, т.к. все работает проблема явно у вас, их админ прислал лог

Причем через какое то время письма начали приниматься нашим сервером хотя я ничего не делал я шас далеко от нашей столицы на отдыхе

Вот 2 сообщения с ошибкой отправки и через какое то время с успешной отправкой

SMTPC" 21260 2308 "2017-11-28 09:38:00.804" "85.236.xx.xx" "RECEIVED: 220 Hello ^_^"
"SMTPC" 21260 2308 "2017-11-28 09:38:00.808" "85.236.xx.xx" "SENT: EHLO WEB2"
"SMTPC" 17392 2308 "2017-11-28 09:38:00.862" "85.236.xx.xx" "RECEIVED: 250-xxx.ru Hello WEB2 [94.130.49.xx][nl]250-SIZE 41943040[nl]250-PIPELINING[nl]250-AUTH LOGIN CRAM-MD5[nl]250-STARTTLS[nl]250 HELP"
"SMTPC" 17392 2308 "2017-11-28 09:38:00.864" "85.236.xx.xx" "SENT: STARTTLS"
"SMTPC" 16392 2308 "2017-11-28 09:38:00.921" "85.236.xx.xx" "RECEIVED: 220 TLS go ahead"
"DEBUG" 16392 "2017-11-28 09:38:00.925" "Performing SSL/TLS handshake for session 2308. Verify certificate: True, Expected remote host name: mail.xxx.ru"
"DEBUG" 17392 "2017-11-28 09:38:00.987" "Certificate verification failed for session 2308. Expected host: mail.xxx.ru, Windows error code: -2146762487, Windows error message: A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider."
"DEBUG" 17392 "2017-11-28 09:38:00.991" "Certificate verification failed for session 2308. Expected host: mail.xxx.ru, Windows error code: -2146762487, Windows error message: A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider."
"TCPIP" 16392 "2017-11-28 09:38:01.049" "TCPConnection - TLS/SSL handshake completed. Session Id: 2308, Remote IP: 85.236.xx.xx, Version: TLSv1.2, Cipher: ECDHE-RSA-AES128-GCM-SHA256, Bits: 128"
"SMTPC" 16392 2308 "2017-11-28 09:38:01.052" "85.236.xx.xx" "SENT: EHLO WEB2"
"SMTPC" 18108 2308 "2017-11-28 09:38:01.105" "85.236.xx.xx" "RECEIVED: 250-xxx.ru Hello WEB2 [94.130.xx.xx][nl]250-SIZE 41943040[nl]250-PIPELINING[nl]250-AUTH PLAIN LOGIN CRAM-MD5[nl]250 HELP"
"SMTPC" 18108 2308 "2017-11-28 09:38:01.109" "85.236.xx.xx" "SENT: MAIL FROM:<no-response@xxx.ru>;"
"SMTPC" 18108 2308 "2017-11-28 09:38:01.163" "85.236.xx.xx" "RECEIVED: 250 OK"
"SMTPC" 18108 2308 "2017-11-28 09:38:01.166" "85.236.xx.xx" "SENT: RCPT TO:<zakaz@xxx.ru>;"
"SMTPC" 18108 2308 "2017-11-28 09:38:16.311" "85.236.xx.xx" "RECEIVED: 550 "HELO must contain a domain name!""
"SMTPC" 18108 2308 "2017-11-28 09:38:16.314" "85.236.xx.xx" "SENT: QUIT"
"SMTPC" 17392 2308 "2017-11-28 09:38:16.368" "85.236.12.22" "RECEIVED: 221 xxx.ru closing connection"
+++++++++++++++++++++++++++++++++++++++++++++++

SMTPD" 9584 60 "2017-11-28 11:50:01.050" "172.16.225.xx" "SENT: 220 smtp.xxx.ru"
"SMTPD" 9584 60 "2017-11-28 11:50:01.058" "172.16.225.xx" "RECEIVED: EHLO sql1"
"SMTPD" 9584 60 "2017-11-28 11:50:01.061" "172.16.225.xx" "SENT: 250-relay1.xxx.ru[nl]250-SIZE 20480000[nl]250-AUTH LOGIN PLAIN[nl]250 HELP"
"SMTPD" 24172 60 "2017-11-28 11:50:01.065" "172.16.225.xx" "RECEIVED: AUTH login bm8tcmVwbHlAcnVzcG9tYWlsLnJ1"
"SMTPD" 24172 60 "2017-11-28 11:50:01.067" "172.16.225.xx" "SENT: 334 UGFzc3dvcmQ6"
"SMTPD" 10920 60 "2017-11-28 11:50:01.070" "172.16.225.xx" "RECEIVED: ***"
"SMTPD" 10920 60 "2017-11-28 11:50:01.079" "172.16.225.xx" "SENT: 535 Authentication failed. Restarting authentication process."
"SMTPD" 10920 60 "2017-11-28 11:50:01.083" "172.16.225.xx" "RECEIVED: MAIL FROM:<no-response@xxx.ru>;"
"SMTPD" 10920 60 "2017-11-28 11:50:01.087" "172.16.225.xx" "SENT: 250 OK"
"SMTPD" 10920 60 "2017-11-28 11:50:01.090" "172.16.225.xx" "RECEIVED: RCPT TO:<zakaz@xxx.ru>;"
"SMTPD" 10920 60 "2017-11-28 11:50:01.094" "172.16.225.xx" "SENT: 250 OK"
"SMTPD" 9584 60 "2017-11-28 11:50:01.097" "172.16.225.xx" "RECEIVED: DATA"
"SMTPD" 9584 60 "2017-11-28 11:50:01.100" "172.16.225.xx" "SENT: 354 OK, send."