Dynamics 365 CE (CRM) Web API Authentication by using ADAL (Active Directory Authentication Library)

d365_webapi_authentication_by_using_ADAL.cs

public string RetrieveAuthToken(string authorityURI, string d365Url, string clientId, string clientSecret)
{
    string result = string.Empty;

    ClientCredential clientCredential = new ClientCredential(clientId, clientSecret);
    AuthenticationContext authenticationContext = new AuthenticationContext(authorityURI, false);

    var authenticationResult = authenticationContext.AcquireTokenAsync(d365Url, clientCredential).GetAwaiter().GetResult();
    result = authenticationResult.AccessToken;

    return result;
}