Generally it seems a lot of people have this issue.
The problem is likely due to the JWT not quite being valid for this call. Or your view isn’t configured correctly.
You didn’t present any code so we can’t debug that.
And you should check that the Config Service is enabled in the dev console and the rigs manifest has been updated.
The config service tab will use the API to set the config.
The optimal way to test this is on the Twitch Website itself where the “system” is more realistic and will have less “fun issues” that the rig likes to manifest.
Personally all my configuration calls are done via the API from the EBS rather than the JS Helper calls.
But you can crack open dev tools and follow the calls and see if you can debug the problem. But best bet is to test on the “real” Twitch website rather than the rig.