We don't recommend implementing clients yourself, and can't provide support under Community Support terms for such cases as well - due to sheer complexity of such task.
You are advised to use existing solutions. There is doc on JScript client that was tested with Gluu Server before [here](https://gluu.org/docs/ce/3.1.6/integration/spa/oauth-js-implicit/). You could study or re-use it for your project.
As for the error you quoted, you need to make sure your OIDC client is registered at Gluu Server, and configured properly. "Properly" depends on a lot of things, in particular on what kind of flow you try to use. You can check [the spec](https://openid.net/specs/openid-connect-core-1_0.html) if not sure.
Unless more details (trafic captures/HAR files, dumps of HTTP requests and responses, logs etc) are provided, it's hard to suggest more than that.