Problematic if not in cloud mode
Once the router is well configured (without cloud), it is impossible to come back and connect again to the router management interface, neither with the dedicated java application, nor via its ip! (login password refused, whatever the browser), and neither via SSH
I'm used to setting up much more complex routers (cisco, watchguard)
You have to do a Hard Reset and reconfigure it to zero like when you unpacked it, in order to be able to set it up again! And I am not the only one in this case, examples, in the forum of the manufacturer: https://community.ui.com/questions/USG-not-allowing-me-to-login-directly/4023a715-d6ab-4b98-a587-f134ee271ffd
As it is, it's not a very serious hardware/software, because they don't correct this login bug in local mode