Create New User Stopped Working! Help!

Hello: I am using WP Members V 2.9.5. It has been working fine for over a year. Just recently, upon New User creation, getting error message “Login Failed! You entered an invalid username or password.” I have tried creating several different accounts with different usernames and passwords and they are all returning the same error message. Can someone please help asap?
My site is http://www.jthoa.com. Thank you!

https://wordpress.org/plugins/wp-members/