Permanent block – A block placed against a sender (panel) by an ISP for exerting characteristics of a spammer, such as having a high number of panelists who mark your survey invitation or reminders as spam. Alida automatically detects blocks from Comcast, Rackspace, Verizon, AT&T, Roadrunner, Hotmail, and Cloudmark. We work to resolve these issues with ISPs on your behalf.
Deferrals & Greylisting – This is is a temporary rejection of the messages by an ISP that forces the sending agent to resend the message at a later time, usually within 24 hours. Some ISPs will increase greylisting when your sender reputation is low.
User-level block – This is a block that is instated by a panelist. It is accomplished by adding the panel's From Address to their email account’s anti-spam settings. Not all ISPs offer this type of an anti-spam feature and bounces from user-level blocks are uncommon.