Make sure your ZD410 printer has the Bluetooth Classic installed. ZD410 printers typically only have Bluetooth Low Energy installed with the default configuration. Run the following SGD command with Printer Setup Utility for Windows to check what Bluetooth capability your printer has and how its Bluetooth is configured.

! U1 getvar "bluetooth"The output looks like something below. Pay attention to the bolded items to make sure Bluetooth is on and discoverable, and it has Bluetooth Classic installed and configured. Hope this helps.
Received:921 bytes 
bluetooth.
bluetooth.discoverable : on , Choices: on,off
bluetooth.friendly_name : XXZJJ174600934 
bluetooth.version : 6.0.1 
bluetooth.date : 12/05/2018 
bluetooth.local_name : XXZJJ174600934 
bluetooth.address : AC:3F:A4:CD:C5:15 
bluetooth.bluetooth_pin : * 
bluetooth.short_address : AC3FA4CDC515 
bluetooth.radio_version : 4.2 
bluetooth.enable : on , Choices: on,off
bluetooth.connected : no 
bluetooth.minimum_security_mode : 3 , Choices: 1,2,3,4
bluetooth.connected_security_mode : nc 
bluetooth.bonding : on , Choices: on,off
bluetooth.clear_bonding_cache
bluetooth.enable_reconnect : iOS_only , Choices: off,iOS_only
bluetooth.le.
bluetooth.le.controller_mode : both , Choices: both,classic,le
bluetooth.le.power_class : 2 , Choices: 1-2
bluetooth.json_config_channel_enable : on , Choices: on,off
bluetooth.page_scan_window : 60 , Choices: 15,60
bluetooth.power_class : 2 , Choices: 1-2