Membership setting cannot be selected

I just created a subdomain page for my online course between WordPress and Learndash. I used the LearnDash Academy to guide me through the registration setup and it still isn’t working to allow the registering option. My test gets a login screen only and login error response.

I believe the problem seems to be with the step of going into my settings on WordPress and selecting the “Anyone can register” box, but it won’t save the setting. I have been trouble-shooting several ways coming up with no solution. I have deactivated some plugins that I thought might be affecting it and even cleared some out that I probably won’t use as it is. I deactivated the theme and used the basic twenty twenty-two. I also did cacheing purges through my browser, wordpress and my host. I even changed the htcaccess setting through my SSL. On the LearnDash support they said it is a WordPress issue. Thank you in advance!

The page I need help with: [log in to see the link]