Originally Posted by
samanway mandal i am running with ios 8.0.2 ....why is it happening????
I don't know why it is happening. It could be caused by a faulty setting, weak wireless signal, a rogue app, etcetera. You can try any of the following to try to fix the issue.
1. Go to Settings - General - Reset and then tap on "Reset All Settings".
2. Go to Settings - General - Reset and then tap on "Reset Network Settings".
3. Call your wireless provider to see if they can troubleshoot from their end.
4. As a LAST RESORT, restore your device and set it up as new.