All of the sudden I can't send e-mail to about anyone as it's been refused with Error 571. I recently updated SmarterMail to 13.2.5507 and then today I noticed 5511 so I updated to that. I haven't touched my configuration and can think of no reason for this to happen, i.e. no viruses or spam issues, all blacklists show me green for 188.8.131.52.
Any suggestions to correct this?
Thank you. HELP