We do not get mails from a specific provider. Their administrator send me this error message. Is it mean the problem is on our side? I'am not friendly with Exchange, how I can fix it, if I can?
Jan 27 10:42:02 lb2 postfix_smtp/smtpd[15284]:
NOQUEUE: reject: RCPT from ketamin.websupport.sk[195.210.29.60]: 550 5.1.1
<[email protected]>: Recipient address rejected: User unknown in relay recipient table;
from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<localhost>