The best way to test network (cloud or network printer) issues is to "ping" the network device from the point of sale device.
1) Download a Terminal Emulation app such as https://play.google.com/store/apps/details?id=jackpal.androidterm
2) Run the app, and type "ping " followed by the IP Address of the device you are trying to connect to. A printer will have an IP Address that starts with 192.168.x.x.
3) To stop the ping, hold the "Volume Down" and press the "c" key.
For a network printer to work, it must respond to the ping command.