I don't know if this is a 100% fix, but I know it works often.
1. Restart your computer.
2. Start GrandChase immediately once you can.
[I recommend placing a shortcut on desktop]
3. The moment you log on, make a room in trial forest and start.
4. If you get into trial forest, complete it, and you've made it past the problem for now
5. This will allow your GC to run for as long as you don't restart.
[Use hibernate instead of restart]
6. If you restart, you must do this over again.
My results, worked fine, after 2 weeks of doing this, the problem disappeared completely. I forgot to do this, and I wasn't booted to pvp lobby ever again.
Good Luck to you all.