HTTP Status 301 'MovedPermanently' error after changing name server

I have a mobile app (iOS, written using Xamarin) which connects to a web service I created. This web service resides on a domain that I own. I recently changed the name server from GoDaddy to InterServer. After allowing 48 hours for propagation, I'm able to consume the web service using a simple .Net/C# test app. However, my iOS app (which is in production and residing on customers' phones), can no longer see the web service. The error is HTTP Status 301 - MovedPermanently. The URL is the same -- only the name server changed so that it's pointing to InterServer (which has the identical code base for my web service that GoDaddy has).

This is a nightmare for my business because my customers can no longer use the mobile app. I could switch back to GoDaddy; unfortunately, they have a whole other set of issues.

Help truly appreciated...