Netsplit - remedy?

Hello everyone,
we got 4 sims. Since 2-3 days i cannot see or enter 3 of them. Others do not share this problem. I have relogged, cleared cache, reinstalled the viewer (emerald and SL), I am not banned, sightdistance is big enough.
I was told that this is called netsplit and would disappear on it's own. But it doesn't. Isn't there anything to do about it?

greetings Aischa

If others aren't experiencing the problem, it's almost surely very local to your piece of network--and most likely right in your router. Try power-cycling everything on the network between your keyboard and the ISP's wall jack.