Auth status code is 200, but response body is 500 internal error

[takaaki.endo]

I tried to auth from Salesforce to Zoom.
Response status code is 200, but response body is
{errorCode=-1, errorMessage=500 Internal Server Error, result=null, status=false}

I referred to the following.

Server-to-Server OAuth

What should I check?

• endpoint
  https://zoom.us/oauth/token