Did you change the password through the control panel yourself (using the Update Password function in the control panel, or the Forgot Password function from the login screen)?
If so, please don’t do that again. Passwords can only be synchronized from the client area to the control panel, not the other way around. So if you change the password in the control panel, the password in the client area will no longer be correct, and various features will stop working.
To fix this, please reset your account password through the client area. Simply find your account in the client area, then click Manage, then go to Edit Account. There you can change the password.