Unable to connect to login server - heeeeeeeeeeelp!

I just downloaded PoE on Steam (and via the PoE website) and when I try to log in, I get the message "cannot connect to login server." This happens with all 3 gateways, not just the America gateway. Here's what I've tried so far...

- Turned off both Windows firewall and virus protection
- Downloaded the web client, created a new account - same error message
- Restarted the PC
- Restarted the router
- Created an exception in Windows firewall for PoE
- Ran Steam as Administrator
- Ran PoE as Administrator
- I can tracert and ping the US login server just fine with no packet loss
- I'm not running any other programs that affect my internet connection, no VPN/other virus software
- I've also verified the game files via Steam, and run PackCheck.exe on the web client install - all to no avail

I'm at a loss as to what could be causing this - any suggestions would be greatly appreciated. Thanks!

I'm able to view the "deal of the day" via the login screen, so there's no connection issue there...