Critial Signing In Problems.

[OBSC]

The first error for signing in was on my mobile device , it said MyBB error something, Next I sign on PC and go to sign in like i have done a million times, And was meet with that username or password doesn't exist, So i do countless password restarts and activation code restarts , after some time they start to work, so I change my password in the control panel and go to sign in, again i see the same message as before that the username or password doesn't exist. I have changed my password again after another restart and i will be logging out now. Hopefully there wont be a problem now. But I believe there will be. Please help me on this issue.