How to allow registration on WP Forum plug-in on blog

[lcptracker]

We are using WP Forum 1.7.5 and need a way to have people register to make comments. Every time we test it, it says that “user registration is currently not available.”
How can we allow visitors to register to ask a question or leave a comment on the forum?

Here’s the site for the Forum: https://www.lcptrackerblog.com/wordpress/ask-a-davis-bacon-expert-2/

Thanks.