Can't Login Main. Help?

So here's the deal. I can't login to my main account. When put my username and password in and hit enter, the load circle freezes and I enter the lobby for 1/2 of a second, only to be placed back on the login screen. I made a new account to see whether or not my computer was the issue. I could login on this account like a charm. If anyone has experienced this problem or knows how to fix it, PM ME ASAP. (My membership is A-Wastin'.) If you need more information about the situation, also PM me.
Thank you,
Red Yakka --99 Slayer--