that sounds like the port forwarding wasn't done properly, as no channel list or search results would be an issue with inbound UDP being blocked, and i would guess uploads don't work? (which would mean inbound TCP not working)
the most common problems are:
for UDP where TCP is working (ie. if uploads work, just not search or the channel list) often people get everything right, except they forget to select UDP for the UDP port (most routers default to forwarding TCP)
if neither works then the common problems are either forwarding to the wrong place (mainly forwarding to the router instead of a computer), or often people who got a separate router for it, but their modem already has NAT in, so effectively you have 2... so it needs forwarding in both (or one needs to be disabled and set to just pass traffic through unmodified, and the other configured)
so of course identifying the problem, do uploads work?