: Office 365 email whitelist It appears as though our server has been blocked from sending emails to email accounts that use office365's MTAs. We run campaigns that send 100's of emails out in

@Samaraweera270

Basically Microsoft's Office 365 servers had decided to greylist us and there was nothing we could do. We actually ended up moving to a hosted service - mailgun in our case which seemed to fix the problem, though we then found that bounced emails were causing us new problems so it's not quite as easy as just throwing money at the problem I suppose.

Shortly before we moved to the hosted service, they greylist was actually removed but we didn't want to risk being re-greylisted.

Advice for anyone else is probably just wait, although it could be a few days :(

Vote Up Vote Down

@Murray155

If your email servers or IP addresses are being blocked it could be for a variety of reasons. There are various organizations and Email blacklist services around the world that exist to prevent spam, mass emailings, virus and worm spreading, and general malicious emailing.

Hostgator has a good writeup on what to do if you're servers or IP gets blacklisted, and how to get it unblacklisted. support.hostgator.com/articles/specialized-help/email/email-returned-blacklisted-or-rejected-by-recipient
Most companies sending mass marketing emails have started using services like Constant Contact or MailChimp to handle their newsletter campaigns. These services are trusted by email blacklist services and capable of sending mass emails on a regular basis.

Vote Up Vote Down