1. Error 404

That means we can't download the configuration of your sGTM.
 
That can be because of:
- sGTM container is deleted
- sGTM container not published
- You use the wrong configuration code
 
If none of the above issues exist, we recommend creating a new sGTM container and using it. You can utilize export and import functionality to migrate your existing configuration.


2. Error 403

Make sure that you're adding the Web GTM container id and not the server GTM container id.
To find your Web container id, you need to open Google Tag Manager and select your web container. There you will be able to see the web container id.


3. Error 500

Facebook recommends removing affected pixels and re-adding them to your CAPI Gateway hub. Basically, you would need to reauthorize affected pixels.

5. Error: 400

400 response for tagging server URL is correct behavior. 
To check if tagging server URL works correctly, you should add /healthy at the end of the URL. If the response is ok, then tagging server URL worked correctly.