Sprint Iphone 4s can't connect to cellular network?

[566]

I have an iPhone 4s with Sprint and have never had a problem with it until now. Sprint has always been slow compared to when I had AT&T but not like this. For some reason, when I try and use some of my apps (instagram, fooducate, my fitness pal, etc) I get an error message from the app (ex. on fooducate it says please make sure your device is connected to a cellular or wireless network and instagram keeps telling me it can't refresh the feed) I went online and googled something to see if the internet worked and it was slower than usual but it still worked (same thing goes for Facebook app). I've tried resetting the network settings and it doesn't do anything. I've also tried restarting the phone with no luck. In the upper left hand corner it still says Sprint, I have all the bars, and 3G so what's the problem? And yes I did pay my bill. Any suggestions would be appreciated!

[Justin]

I have fooducate too and it's not working either. I get the exact same message. There are reviews on the app and other people are having issues. I've heard that instagram is having problems to. As for my fitness pal I have that app and it works for me.