What is your router's model number? You can easily search up what is the default username and password for factory default routers so you can get in your router's settings.
Its something with TG862 ARRIS Xfinity
my father set a password on it but doesn't know it anymore.
I am pretty sure UPnP was enabled on the router, my dad didn't change any settings as far as I know when we first got it.
So when It was reset it probably has it on now.
Blockland seems to Identify the UPnP but says miniupnpc error -1.