Are you able to send messages ok when you switch to a WiFi connection? Or, do you still have problems there too?
If you still can't send them, over a wireless connection, it's worth contacting Snapchat for further assistance. You can find their support page at Snapchat Support. There may be an issue with your account.
Did you ever get to the bottom of your problem???
My daughter and I are having the exact same trouble, snapchat works over wifi and on other mobile networks but for some reason neither of us can login using the BT mobile cellular network.
Kind regards, Matthew
I have the same problem. I can use Snapchat on WiFi, but not on BT Mobile's mobile data.
Did any of you resolve this problem? My son has moved to iphone 5s and is having exactly the same problem - Snapchat works fine over Wifi, but will not work using mobile data. All over apps use mobile data just fine, it is only snapchat that has a problem.