I am trying too integrate with Skype for Businesses Online using UCWA 2.0 to be able to schedule online meetings. However I am running into a challenge while using REST APIs . I have successfully registered my application with Azure AD however while trying to obtain Acceess token using POSTMAN I am unable to do so .I have added the following Auth UR https://login.microsoftonline.com/tenantname.onmicrosoft.com/oauth2/authorize?resource=https://webdirin1.online.lync.com & Access URL https://login.microsoftonline.com/tenantname.onmicrosoft.com/oauth2/authorize . I have also provided the client id and secret available in the portal. Iam presented on screen to login. After putting the credentials it says request could not be completed.
You should have a look at the getting started documentation of the SDK which would help you getting the token in a web context.
Otherwise if you're doing dotnet or any other server side/integrated app development have a look at the ADAL library