Guide to resolving ISP issues

I often get a chuckle out of watching some people, who are normally on the blocking end of the delivery equation, struggle through their own blocking issues. A recent situation came up on a mailing list where someone who has very vehement opinions about how to approach her particular blocklist for delisting and that the lists policies are immutable. The company she works for is having some delivery issues and she’s looking for a contact to resolve the issues.
While digging through my blog posts to see if there was any help I could provide, I realized I don’t have a guide to resolving blocking issues at ISPs. Much of the troubleshooting can be done without ever contacting the ISPs or the blocklists.
Identify the issue.
There are a number of techniques that ISPs use to protect their users from malicious or problematic mail, from rate-liming incoming mail, putting mail in the bulk folder, or blocking specific IP addresses. Step one to resolving any delivery problem is to identify what is happening to the mail. In order to resolve the issue, you have to know what the issue is.
All too often, the description of a delivery problem is: My mail isn’t getting delivered. But that isn’t very clear as to what the actual problem is. Are you being temp failed? Is mail being blocked? Is mail going to the bulk folder? Is this something affecting just you or is it a widespread problem?
Troubleshoot your side.
Collect as much data about the problem as you can. Dig through logs and get copies of any rejection messages. Follow any URLs that are present in the bounce messages. Try sending a bare bones email to yourself at that ISP with just URLs, is it still blocked? What if you send from a different IP, does the same thing happen?
There is a lot of troubleshooting a sender can do without having to contact an ISP, and the information can lead to resolution that doesn’t involve having to contact the ISP. Also, many current ISP blocks are dynamic, they come up and go down without any human intervention. Those blocks that require contact to get them resolved have clear instructions in the bounce message.
Fix your stuff.
Whether it’s a reputation issue or a minor technical issue, fix the problem on your end. Just moving IP addresses or changing a URL isn’t a sustainable fix. There is a reason mail is being blocked or filtered and if you don’t fix that issue, the blocks are just going to come back. After you do fix your stuff, expect to see changes in a few days or a week. The ISP filters are generally quite responsive to sender improvements so if you’ve fixed the stuff you should see changes pretty quickly. Expect unblocking or filtering to take a little longer than the block was in place.
If you can’t figure out what the problem is, hire a consultant. Here at Word to the Wise we can often quickly identify a problem and provide a path to resolution. Sometimes the problem isn’t even the ISPs, we’ve had multiple cases where our clients were using custom software and their software wasn’t SMTP compliant and we were able to identify the problem and get their mail working again. There are a host of other independent consultants out there that can also help you identify and resolve blocking problems.
Contact the ISPs.
If there is a hard block or after fixing what you think the underlying problem is, you’ll have to contact the ISP. Many ISPs provide self service websites and contact forms to facilitate this process. Generally, though, most issues aren’t going to require contact.