I’ve been getting quite a few emails from people wanting to know if I’ve made any progress on the deliverability issues I was facing when delivering email to outlook.com. As good fortune would have it, Microsoft accepted my request to delist my mail server from outlook.com’s internal IP blocklist.

Recently, I was trying to respond to an email delivered to me from an outlook.com sender address. Unfortunately, my response immediately bounced back, and I was informed that my mail server’s IP address had been added to outlook.com’s internal blocklist.

A while back I did some consulting work for a small ISP who had received complaints from a few customers that believed they could not use the ISP’s SMTP server to send email to outlook.com or hotmail.com accounts. These customers claimed they never got any bounce message (Non-Delivery Report)  in return, so they firmly believed the problem resided with the ISP.