hi wyzwolenia, This problem can occur if the sending domain uses more IP addresses to send emails (e.g. gmail). If the IP address changes after temporary reject by greylisting, new connection cannot be paired with the one that already exists in the greylisting database. and/or Receiving domain uses more servers to receive emails. If the receiving server changes between temporary rejects, a new record has to be added to its greylisting database. (assuming you have V6 version of EMSX) If it is the first case, you could add domains like gmail.com to "Domain to IP whitelist" (Server/Antispam protection/Greylisting), this should help. You can also try to increase the "Unverified connections expiration time (hours)". There is no solution for the second case yet, but EMSX v6.4 will be able to share greylisting databases between servers using ESET cluster. filip