We have generated access token using oauth2.0 using URL login.microsoftonline.com/{Directory (tenant) ID}/oauth2/token
with scope: openid offline_access xxx.xxx.dynamics.com/.default
But it is not valid for accessing create phone call activity API (Failure reason is unauthorized)
But when we generate an access token using password and grant type password and resource= our CRM instance URL then it is valid
What should be the scope/configuration needed, so that access token is valid for creating phone call activity API od Dynamics 365