Major deliverability issues

For the past several months, we've experienced extremely poor open rates - indicating to me that most of our emails are not even making to the users' inbox.  I contacted CM support this afternoon regarding a specific instance where there was one company (AT&T) where all of the emails sent to all contacts resulted in a General Bounce.  I even tried sending a test email to a friend that works there and she's added our email address to her contacts - but still no luck.  Campaign Monitor support responded with the following response (and said they would be posting a notice out to the blog to alert the rest of the Campaign Monitor community):

Unfortunately this is an issue on our end. MessageLabs is currently blocking all emails from our servers, which includes We are aware of the issue and have been actively working with them on removing the block, which has been slow going, I hate to say.  Our last correspondence was with the Asia Pacific Support manager who is tiring to tell us that the blocked messages are due to the content of the messages not an IP or domain based blacklist. This is even though they are blocking all messages from our servers.  Their support staff have also told us that the subscribers (their customers) need to white list our sending servers and domains within their Message Labs customer portals. As ridiculous as this is we have actually tried to contact the administrators of as many domains that we have identified as using Message Labs and asked them to do this. We'll continue to work on the problem and escalate through their company but it may take some time to get a result.

While this took me by surprise and threw another wrench into our situation, I'd like learn from other members if they too are experiencing deliverability issues to their subscribers.  We abide by most best-practices when it comes to ensuring that our emails are not flagged as spam by our subscribers' email servers.  We send B2B emails - meaning most of our emails are sent to corporate email servers, not commercial ISPs like yahoo, gmail, hotmail, aol, etc.

Also, if anyone has any specific tips to further improve deliverability in a B2B environment, that would be helpful.  Look forward to your responses.


Mathew Mathew, 6 years ago


For information on the MessageLabs issue, please see our blog post at

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