Google API authentication: Not valid origin for the client

I received the same console error message when working with this example: https://developers.google.com/analytics/devguides/reporting/embed/v1/getting-started

The documentation says not to overlook two critical steps ("As you go through the instructions, it's important that you not overlook these two critical steps: Enable the Analytics API [&] Set the correct origins"), but does not clearly state WHERE to set the correct origins.

Since the client ID I had was not working, I created a new project and a new client ID. The new project may not have been necessary, but I'm retaining (and using) it.

Here's what worked:

• Create a new project
• Add and Enable the Analytics API
• Create a new credential - ensure that it is an OAUTH credential (scroll to the bottom of this page for instructions https://developers.google.com/api-client-library/javascript/start/start-js#Setup).

During creation of the credentials, you will see a section called "Restrictions Enter JavaScript origins, redirect URIs, or both". This is where you can enter your origins.

Save and copy your client ID (and secret).

My script worked after I created the new OAUTH credential, assigned the origin, and used the newly generated client ID following this process.

Clear your browser cache. Started getting this error in Chrome and then I created a new client id and was still getting the issue. Opened firefox and it worked, so I cleared the cache on Chrome and it started working.

Key Point: Add both http://localhost and http://localhost:port_number to the Authorized JavaScript origins box for local tests or development.

try clear caches and then hard reload, i had same error but when i tried to run on incognito browser in chrome it worked.