I've got the same problem when I have send mail:
SMTP error from remote mail server after end of data: host 198.91.80.251 [198.91.80.251]: 450 4.4.1 id=00493-14 - Temporary MTA failure on relaying, Can't connect to INET4 socket 127.0.0.1: Connection refused, MTA([127.0.0.1]:10030), id=004...