Call to an external API fails only from mobile device


I am seeing a strange behaviour where my meteor server call to an external API is failing only when I call the meteor responsive website from a mobile device. That too no all aPI calls are failing only 1 out of 3 API call is failing. Can you pls let me know how to debug? I have deployed the app on and I would like to know how to debug these kind of issues. Also any thought on what the problem is would be helpful