Temporary Delivery Problems for Yahoo, Hotmail Addresses


UPDATE: Campaign Monitor’s IP addresses have been taken off the Spamhaus blacklist. Because of cached settings, you might still experience a few bounces, but they will reduce gradually.

Earlier today a blacklist, Spamhaus, added Campaign Monitor’s IP addresses to its list because of one or more complaints about a particular campaign sent by one of our customers. That list is used by some email providers as a way to prevent spam.

In this specific case, many emails to Yahoo and Hotmail, as well as other email providers which use Spamhaus, are being blocked. If this has happened to your campaign, you will see mailblock bounces in your reports. Test emails to these addresses are also affected. It is not possible to know which systems are using this blacklist as part of their filtering unfortunately.

It is a part of every email service providers role to monitor for these listings, which inevitably occur, and take immediate action to remove them.

What is being done about it?

We’ve already contacted Spamhaus, explaining our strict anti-spam policies and procedures, and offered information about the specific email in question.

We have also had our upstream hosting provider (top level owner of the IP addresses) following up on our behalf.

How does this affect my clients?

We will be putting a notice up in your client’s accounts, so when they go to create a campaign they will be warned of this problem. It will not give away anything about Campaign Monitor though, so it won’t impact your rebranding.

When will this be fixed?

Unfortunately, at this point we can only wait for that block to be removed. At this stage, we do not have a time frame as to when that will be done.

Will those emails be resent once the block is lifted?

We won’t automatically resend them, as we understand that some emails need to go out at a certain time, or not at all. However, if you contact us we will be happy to credit your account for the failed emails.

Will you let me know when it is fixed?

We will update this blog post once we have confirmation that the issue has been resolved. We’ll also update our twitter account with any changes.

Can I send my next campaign anyway?

If your list contains few Yahoo or Hotmail addresses, and is mostly to specific business domains, this listing might not be an issue for you.

Another alternative, if you need to reach your subscribers right away would be to create a segment that has all the people who are not using Yahoo or Hotmail addresses.

One rule you would need is ’email address DOES NOT CONTAIN “yahoo”, for example. That would give you a list of everyone else that you could email without paying for emails that can’t get through.

How will you stop this happening again?

We have many different tools we use to prevent and resolve these types of problems, including software monitoring, bounce log reading tools and other external systems.

We can never guarantee it won’t happen, but we do work very hard to maintain our excellent sending reputation. Unfortunately, the nature of blacklists is that anyone can complain about an email, rightly or not, and the onus is on us to follow up.

We’re very sorry to cause you and your clients any delay or hassle, and we’re doing everything we can to get it sorted out for you.

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