SMTP issues

MailCleaner Support
Added 11 days ago


  • Could not complete sender verify
Incoming MTA stage: 2019-07-09 17:07:46 H=(hostname.domain.tld) [xxx.xxx.xxx.xxx] F=email@sending-domain.tld temporarily rejected RCPT email@receiving-domain.tld: Could not complete sender verify"

MailCleaner attempts to validate the sending email address before accepting the email. We do this by issuing a RCPT TO command to the sending email server with the senders email address. If the sending mail server responds with a 250 command, we know the sending email address exists and therefore accept the message. The main reason that the sender verify can fail is because the remote mail server does not conform to standard RFCs.

You may want to ask the administrator of the sending domain to ensure their mail server complies with RFC 2821 #4.5.3.2.

https://www.ietf.org/rfc/rfc2821.txt