Monitoring and troubleshooting: how to use seed tests, blocklist checks, analytics

Even with good practices in place, deliverability issues still happen. Monitoring your sending health and knowing how to troubleshoot problems quickly is a critical part of keeping your emails in the inbox.

Using block responses
If your mail is getting blocked, the first step is to look at the block responses from the receiving server. These error codes often tell you exactly what is going on and how to fix it. Sometimes it means your IP or domain needs to be delisted from a Microsoft block list or a Spamhaus block list. Other times it is a temporary deferral because you sent too much, too fast. Reading the responses carefully can save hours of guessing.

Blocklist checks
If you suspect your domain or IP has been flagged, run a blocklist check. Many services make it easy to see if you are listed, and most block lists provide a way to request removal once you have addressed the underlying problem. We recommend MX Toolbox. 

Analytics and internal reports
Most deliverability problems do not show up as blocks. If you see low open rates, declining click rates, or employees report that messages are landing in spam, it often points to a reputation issue rather than a block. In those cases, the best step is to tighten your segmentation. Focus only on subscribers who have engaged recently until open rates and inbox placement recover.

Troubles during warmup
Warming a new IP or domain can be especially tricky. Sometimes Gmail will send everything to spam from the get go. In these cases, you need to send repeatedly to a seed list of friends and family who will consistently open your email and/or a very small engaged group, slowly inserting your real customer list into daily sends. It is tedious, but consistent positive engagement is the only way to build trust with inbox providers during warmup.

Key takeaway
Monitoring and troubleshooting deliverability is about reading the signals inbox providers give you. Block responses, blocklist checks, analytics, and seed tests all provide clues. Whether you are fighting a block or trying to climb out of spam placement, the solution almost always comes back to showing ISPs that your subscribers want your emails.

In the final article of this series, we will look at the future of deliverability and how trends like AI filtering and new privacy standards are shaping the inbox.

Next article →

This post is part of our deliverability series. Check out the full guide here.