how to allow user registration?

hi,

i have just worked out how to add a “claim listing” button to the sidebr. However, when i click the button, as a non-registered user, i am presented with a window asking to me to log in, with the option to register also. But when i click to register, i am given a “Heads Up!
User registration is currently not allowed.” message.

As usual, i m alooking eveywhere to try to find where to allow use registration, but no joy 🙁

Any help appreciated. Thank you!