Custom subdomain on shopify gives http error 400, can't connect to server debug mode


Sorry for opening another topic but it looked like the other topic is abandoned and I still have a problem: My custom subdomain ( is giving a http error 400 when being opened which causes it not to load in the debug mode in gtm so I can’t check if the tags are working.

It shows in your service that request are being send and I don’t understand this. What is going wrong and how do I fix the http error 400? (It appeared after deleting the CNAME file like suggested on the forum).


Your custom subdomain is set up correctly; it should have 400 response.

When I check your site, I see that GA sends requests to the correct subdomain. It looks like everything works correctly. Try to wait longer; sometimes, server container debug mode has a significant delay.
Screenshot 2021-06-01 at 09.05.57

Oh ok that’s great to hear. I’m gonna setup the server side tagging via the facebook pixel on my shopify store. Any idea how im gonna test this if the debug mode isn’t working? Thanks for all the help!

It’s a non-standard issue that debug mode doesn’t work. Maybe try to use another browser or clean cookies?

Thanks for the response! I’ve found the problem, Im very new to all of this so I did not understand that I had to check from my main domain instead of the subdomain. Now I checked de debug preview from my main domain and everything is working. Thanks for all the help!