this just happened out of the blue - was working fine last week now it's not. I went to login at amsdv.com/login and my admin password wouldn't work. used password reset, received email, clicked link, reset password. still no luck logging in.
Got the "Sorry, that key does not appear to be valid" error.
used the trick adding wp_st_password('password',1); to reset password. went to amsdv.com/wp-login.php and entered admin username and new password. redirects to my themed login page; prompting me to login in again.
I can register as a new user. just can't log in as admin.