Unable to sign in

Common reasons that you can't connect to the servers, experience disconnects, or just have lag in general...

1. You don't have the three .exe files for the client set to run as administrator.
2. You don't have the game directory set as an exception in your security softwares.
3. Your network adapter driver is out of date and needs to be refreshed.
4. Your local area network settings are improperly configured.
5. You have more than one firewall and don't realize it.
6. Your firewall settings are too strict. (Very common with ZoneAlarm and Commodo firewall.)
7. Your router is configured improperly.
8. you have a bad network cable.
9. You're using a wireless network connection. (Which leads to another huge list.)
10. You have a lot of traffic on your local network that is bogging your router/modem down.
11. There's a fault in your router.
12. There's a fault in your modem.
13, You have a bad phone cord plugged into your modem.
14. There's an issue with your house wiring.
15. There's an issue with your outside wiring.
16. A squirrel chewed on your phone line at the pole and it's raining. (I've had this happen personally.)
17. A switch/router at the CO for your ISP is having an issue.
18. One of the many hubs between you and PWI is having an issue. (most common)
19. There is heavy sunspot activity. (has happened within the past two years)
20. There's a regional router outage. (Has happened several times, most recently just a couple of months ago.)

That's just a few. The more details you give, the better I can narrow it down and tell you what the issue is.

Also, post a copy of a traceroute to the server.