Restart your device. It might sound simple, but sometimes that’s all it takes to fix a bad connection.
If restarting doesn’t work, switch between Wi-Fi and mobile data:
Go to Settings and then Wireless & networks or Connections.
Turn Wi-Fi off and mobile data on, and check to see if there’s a difference.
If not, turn mobile data off and Wi-Fi on and see if that works.
Try the troubleshooting steps below.