Investigate router ir access point issues
If you're connected to hotspot or domain network,contract the network administrator.
Otherwise:
1. Unplug or turn off the device.
2. After all the lights on the device are off,wait at least 10 seconds.
3. Turn the device back on ir plug it back on or plug it back into the power iutlet. To restart a router or access point that has a built-in batterry,press and quickly release the Reset button.