While calling endpoint API, sometimes we are getting 500 Unknown error from server, but most of the time API works fine. And also in case of 500 Unknown error, we are unable to see any logs in google console logs. API response takes 2 sec approx. We are using App engine Java deployment.
Can anyone help me find the root cause of this problem?
Following is the chrome console error /conge-portal/#!/dashboard/myage:1 XMLHttpRequest cannot load https://a-master-server.appspot.com/_ah/api/ageEndPoint/v1/aghie…5648/674390454714943921958166322392772?showTarget=true&month=May&year=2017. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost' is therefore not allowed access. The response had HTTP status code 500.
Issue stopped after migrating to endpoint framework 2.0