UPnP means Universal Plug 'n' Play, this means you shouldn't have to port forward aswell... You should just enable, and magic; it works!
You CAN enable port forwarding and UPnP at the same time... It just seems to make Blockland hosting unreliable.
UDP is only required for port forwarding, I think I posted my first post while high or something.
Thank you Jetz for useful snip.