If is good to you, I signed using a yahoo account without problems.
@the player
This is a common problem know as lag. It have three factors in this case
1. the distance between you and the server. You know that the server is in china, and because that the lag issue will be more often and anoying that othergames
2. your current connection. To play smootly, you must have a good connection. minimum of 10 mb. With less is possible play but maive have connection drops.
3. the curent loads of the server. If the server have mutch players connected the lag will be more.
The most common problems with the lag are:
disconnect after minutes of play, if the game can't stablish a good connection with the server.
The enemies can attack you when are far to you.
You can't dettect any player or enemy because the game can't load it because can't ask to the server if some player or enemy are in the area that you are walking
In sumary
you have to try with a better internet connection, or play in a diferent time. Try to enter when aren't playing the chinece players.