As opposed to a blacklist, a greylist is typically considered a “cautionary” list. It marks IPs, URLs, and/or sender information the recipient may want to watch or track. If a sender is on a greylist, they shouldn’t see much (if any) impact on overall deliverability. Another usage of the word “greylisting” is when the receiver returns a transient/temporary delivery error for a message. If the sender attempts to reconnect and send the same message again, the receiver then accepts it. GetResponse is configured to automatically retry transient errors for you for optimal deliverability.

...почемувы уходите?я непонимаю!Ну зачем так?Постойте!
Не уходите! Дайте нам шанс!