Showing results for 
Show  only  | Search instead for 
Did you mean: 

Dynatrace HTTP errors almost all "unknown"


Hello, in one of my tenants, I see that almost all HTTP errors have an <unknown> response code. Has anyone else seen this? How can I identify what their response codes were?


If I dig into the first one, I get

When I go into the first couple user sessions who were "impacted", none of them have an action related to the name of this error.


How should I go about troubleshooting this?


Dynatrace Leader
Dynatrace Leader

Hey, Brett B.

First off, I am sorry that we let you and others done by not making this explicit in the first place. I totally I acknowledge that in prior versions it was definitely misleading!

Let me assure you we are aware of this and we fixed this starting with 1.207 where we renamed it to "Failed images" (to what it is!). And let me give you a quick peak into how this is going to look like with 1.208/9 (January next year).

More detail: we are using browser APIs to tell us whether an image failed. Downside this API (in essence a JavaScript listener) doesn't provide us with the info why it failed, while it could actually fail for two reasons:

  • during the request, or
  • during the paint.

This means, it could also be listed because the browser detected issues during the painting phase of that image. So this error is a bit tricky to reproduce. While this is tricky to interpret we still believe that it's helpful. But in essence as with many other things we just passing/bubbling up all the info we get from the browser and it's APIs.

Hope that helps and made it clear and looking forward to your thoughts!



Hey Thomas,

Thank you for this very detailed response. Yes, it does make it clear and I look forward to 209! I'll share this with my customer

Featured Posts