I have a problem with postfix. Our server not accepting the emails from a domains.
On the receiver server logs I see:
postfix/smtpd: improper command pipelining after DATA from mail.domain.hu[IP address]: postfix/smtpd: lost connection after DATA (0 bytes) from mail.domain.hu[IP address]
On the sending server logs (it uses exim4):
R=lookuphost T=remote_smtp defer (110): Connection timed out: SMTP timeout while connected to domain [IP]
Does anyone have a suggestion what can cause a problem like this? Can a bad (self-signed) SSL cert on the receiving server cause this?