You can turn off the Connection Optimizer, if it's on.

• Settings → More Networks → Mobile Networks → Connections optimizer → Turn off Connections Optimizer, or turn off Wifi Timer

• Settings → Wifi → Tap the vertical ... and then Advanced → Wi-fi Timer → There turn off any timer selected.

I hope this works for you.

Turn off Connection Optimizer

• Settings -> More Networks -> Mobile Networks -> Connections optimizer -> TickOff connections Optimizer

Or Turn Off Wifi Timer

• Settings -> Wifi -> Tap the vertical ... and then Advance -> Wi-fi timer -> Turn off any timer selected.

I hope this works for you.

Turn off Connection Optimizer

• Settings -> More Networks -> Mobile Networks -> Connections optimizer -> TickOff connections Optimizer

Or Turn Off Wifi Timer

• Settings -> Wifi -> Tap the vertical ... and then Advance -> Wi-fi timer -> Turn off any timer selected.

I hope this works for you.

You can turn off the Connection Optimizer, if it's on.

• Settings → More Networks → Mobile Networks → Connections optimizer → Turn off Connections Optimizer, or turn off Wifi Timer

• Settings → Wifi → Tap the vertical ... and then Advanced → Wi-fi Timer → There turn off any timer selected.

I hope this works for you.