SMTPDebug еще не выполнял.
Вот какая информация имеется:
03.09.2015 16:34:37 [31637:00036-993695488] SMTPClient: Attempting to Connect: Host mail.ДОМЕН_ПРИНИМАТЕЛЯ, Port 25, SSL Port 0, Connecting Domain ДОМЕН_ОТПРАВИТЕЛЯ
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Connection successful
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 220 *****************************************
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: CommandEHLO: EHLO ДОМЕН_ОТПРАВИТЕЛЯ
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-ДОМЕН_ПРИНИМАТЕЛЯ is pleased to meet you
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-DSN
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-SIZE 31457280
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXXXXXA
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-AUTH LOGIN PLAIN CRAM-MD5 DIGEST-MD5 GSSAPI MSN
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-ETRN
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXB
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXC
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXXXXXXXXXXD
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-8BITMIME
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXE
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-PIPELINING
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 XXXF
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: SMTP Authentication is not required by local server. Username: -blank-
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Attempting to SubmitMessage:
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Pipelined commands:
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: MAIL FROM:<отправитель@ДОМЕН_ОТПРАВИТЕЛЯ> SIZE=3624
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: RCPT TO:<получатель@ДОМЕН_ПРИНИМАТЕЛЯ>
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: RCPT TO:<получатель@ДОМЕН_ПРИНИМАТЕЛЯ>
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: DATA
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: End of pipelined commands
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 отправитель@ДОМЕН_ОТПРАВИТЕЛЯ sender accepted
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 получатель@ДОМЕН_ПРИНИМАТЕЛЯ will leave the Internet
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 получатель@ДОМЕН_ПРИНИМАТЕЛЯ will leave the Internet
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 354 Enter mail, end with "." on a line by itself
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Data Send Succeeded 2682 bytes
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 4246171 message accepted for delivery
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Attempting to Disconnect:
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: CommandQUIT:
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: ReceiveResponse: 221 ДОМЕН_ПРИНИМАТЕЛЯ CommuniGate Pro SMTP closing connection
03.09.2015 16:34:38 [31637:00036-993695488] SMTPClient: Connection terminated successfully
03.09.2015 16:34:38 Router: Transferred 1 messages to ДОМЕН_ПРИНИМАТЕЛЯ (host mail.ДОМЕН_ПРИНИМАТЕЛЯ) via SMTP
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Connection terminated with status: 2055
03.09.2015 16:37:04 Router: No messages transferred to ДОМЕН_ПРИНИМАТЕЛЯ (host mail.ДОМЕН_ПРИНИМАТЕЛЯ) via SMTP: The server is not responding. The server may be down or you may be experiencing network problems. Contact your system administrator if this problem persists.
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Attempting to Connect: Host mail.ДОМЕН_ПРИНИМАТЕЛЯ, Port 25, SSL Port 0, Connecting Domain ДОМЕН_ОТПРАВИТЕЛЯ
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Connection successful
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 220 *****************************************
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: CommandEHLO: EHLO ДОМЕН_ОТПРАВИТЕЛЯ
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-ДОМЕН_ПРИНИМАТЕЛЯ is pleased to meet you
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-DSN
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-SIZE 31457280
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXXXXXA
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-AUTH LOGIN PLAIN CRAM-MD5 DIGEST-MD5 GSSAPI MSN
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-ETRN
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXB
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXC
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXXXXXXXXXXD
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-8BITMIME
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-XXXE
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250-PIPELINING
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 XXXF
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: SMTP Authentication is not required by local server. Username: -blank-
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Attempting to SubmitMessage:
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Pipelined commands:
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: MAIL FROM:<отправитель@ДОМЕН_ОТПРАВИТЕЛЯ> SIZE=4508
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: RCPT TO:<получатель@ДОМЕН_ПРИНИМАТЕЛЯ>
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: RCPT TO:<получатель@ДОМЕН_ПРИНИМАТЕЛЯ>
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: DATA
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: End of pipelined commands
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 отправитель@ДОМЕН_ОТПРАВИТЕЛЯ sender accepted
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 получатель@ДОМЕН_ПРИНИМАТЕЛЯ will leave the Internet
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 получатель@ДОМЕН_ПРИНИМАТЕЛЯ will leave the Internet
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 354 Enter mail, end with "." on a line by itself
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Data Send Succeeded 3166 bytes
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 250 4246188 message accepted for delivery
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Attempting to Disconnect:
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: CommandQUIT:
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: ReceiveResponse: 221 ДОМЕН_ПРИНИМАТЕЛЯ CommuniGate Pro SMTP closing connection
03.09.2015 16:37:04 [31637:00036-993695488] SMTPClient: Connection terminated successfully
03.09.2015 16:37:04 Router: Transferred 1 messages to ДОМЕН_ПРИНИМАТЕЛЯ (host mail.ДОМЕН_ПРИНИМАТЕЛЯ) via SMTP