Worker Custom Domain messing up top domain

We added Custom Domain to a Worker to point to and that works fine, however the top domain ( is randomly serving the Worker instead of the expected original response (a HTTP 301 redirect to

Is there something we can fix on our side or is there a bug in Custom Domains Worker feature that CF needs to fix to make it work reliably?

Note - I am only allowed 1 embedded media ¯_(ツ)_/¯ here are the 2 responses:

![correct redirect|690x384](upload://paUkHA0eCnueBKsCLk1pqUkvnOy.png)
![incorrect worker|690x278](upload://7mgGX8rDpQlUgRu5uGcWSGwKhwv.png)

incorrect response:

correct response:

I confirm this problem, This also happened on my any subdomain which “Proxied” on.

My all subdomain randomly serve worker’s response so it’s mess up my whole website…

Workaround we are using for now:

  • in Worker → Triggers, remove the Custom Domain and add a Route
  • in Website → DNS, add a CNAME record from the subdomain to the original route

I can confirm this is an issue too. Definitely do not use Custom Domains for workers if you have multiple subdomains! The responses get mixed up between different subdomains as soon as you do so, which can have really bad effects on a production site. It is of course my own fault for using a beta product in production ;). Reverted back to a dummy CNAME for the worker

Another thing to note, afterwards you need to flush your DNS cache on e.g. Chrome, because for me the whole change poisoned my DNS cache, leading me to a very generic “403 forbidden — Cloudflare” nginx-esque page for all subdomains associated with the one where I activated custom domains for workers.

I will stress again - do not use this in production. It’s been a pain dealing with the after-effects

This topic was automatically closed 15 days after the last reply. New replies are no longer allowed.