I want to integrate OAuth authentication for procore in my app.But Im getting this error :
Client authentication failed due to unknown client, no client authentication included, or unsupported authentication method.
I have included client id,code as well as redirect-uri parameter in my url:
https://login.procore.com/oauth/authorize?client_id=<my-id>&response_type=code&redirect_uri=<my_url>
I just ran into same issue, however I've been trying to use sandbox client_id. In this thread Procore Client authentication failed due to unknown client, no client authentication included, or unsupported authentication method I found that you have to use login-sandbox.procore.com instead of login.procore.com for sandbox client_ids.
Fixed the issue for me