Try these or maybe a different client.

gnutella.hostscache.com:6346
gnutella.hostcache.co.uk:6346
gnutellahosts.com:6346
router.limewire.com:6346
gnet.ath.cx:6346
gnet2.ath.cx:6346
connect.newtella.net:6346
cache.gnuranium.com:6346
connect1.gnutellanet.com:6346
connect2.gnutellanet.com:6346
connect3.gnutellanet.com:6346
connect4.gnutellanet.com:6346

I am using BearShare and it is slower getting connect then before, but I have never not been able to get connected.