Hi Matt,
first check that the Shelly is present on your network. Either:
go to the Shelly app and check the device under Settings / Device info and check the IP address and signal strength.
and / or
ping the device from you PC (in dos window: ping 192,168.2.49 ) and you should get 4 positive responses.
If the device is in your network, your command is correct and should work from a web browser.
Once you can control it from the web browser, then just replicate the command in Loxone on a virtual output.
My bet is the device has not joined your network, so just go thought the reset and install procedure.
Shout if you need more advice,
Cheers David