Web API App-Only with Graph API

create-access-token.cs

[HttpGet]
public async Task<IActionResult> Get()
{
  AuthenticationResult authResult;
  try
  {
    authResult = await this._authContext.AcquireTokenAsync(this._graphUrl, this._credential);
  }
  catch (Exception ex)
  {
    var result = new JsonResult(ex);
    return result;
  }

  ...
}