I'm playing Dark Souls 1 on Steam and few days ago I noticed that I can't connect to any other world: Invasions fail, White sings used by nobody, I don't see any messages. The game failed to work online before, but I always got warnings about it and Orbs would simply become unusable, which is not the case this time. All that is tested with 2 chars in different areas.
I installed Dark Souls PVP Watchdog and confirmed that I am connected to 0 players all the time.
Reinstalling didn't help. Download region is set and the same as usual. What else can I try to fix this problem?