Using Self Client to Use Projects API

Using Self Client to Use Projects API

I registered self-client in the app registration. However, I saw in the steps to request authorization that I need a redirect_uri. Using self client, I don't have a request_uri. Is there a way to use self client and use projects API?

Based on my research, this seems possible with Zoho CRM: Kaizen #2 - OAuth2.0 and Self Client #API (zoho.com). I actually followed the steps on the link I provided, and I was able to generate access tokens. But it seems it's only applicable to Zoho CRM APIs because when I called a Zoho Project API using the access token I generated, I'm getting the error "Invalid OAuth access token."