cannot print

[keesoon]

it show ready but also not connected, and the other of the device are working totally fine. only some of the device with this problem.

[Candlestore]

@keesoon ;

As I see this is your first post welcome to the sellers community forum.

Since your stating the Printer is Ready but also Not connected, I have had this problem also after a poweroutage or the power flashes.  My printer would show ready, but would get a different IP address from the router.  I have since changed the Router settings to give the Receipt Printer a Static IP Address.   The other thing I notice is on your image You have 3 different Network connection strenghts, are you sure your device is on the samenetwork as the printer?

If you can see if the Receipt printer can print a Configuration file, such as IP address, Network it is on and maybe MAC address.  My Star printer can do this but I need to read Help articles to do this.  Then check your Square Printer Profiles and make sure these settings match what is configured in Square for that printer.

[keesoon]

i try to search the printer ip from the app in advance printer setup and i try to enter the static ip from the printer, it work~i can search the printer and ready to use but when i try to print the resit, it will going back to Not connected. i also try close all other network except for the one wifi link to printer but still also the same problem.

[Candlestore]

@keesoon ;

Sounds like you may have the Printer Profile sending the receipt to the wrong printer.

Last year Square Changed Printer setting that you have to setup a Printer Profile so that when your setting up another device you do not need to go through the process of setting up all connected hardware again.  Since your printer is on a network I would look into the printer profiles setting and on your pos see which printer profile you need that was setup earlier.

Here is more about Printer Profiles :  New-Printer-Profiles/m-p/692921