Locked out from admin console

Hi,

I"ve been using Openfire 3.9.1 for about a week. It's works fine but today when I tried to log in into admin console I get a message that my login or password incorrect or user is not an administator. But I used default admin account. My password is 100% correct because I still can use admin account via spark client and send messages. Any ideas why I cant log in into admin console and what should I do?