It’s telling users that they missed a field and refuses to register a new member but all the fields are filled in. What are we missing?
Registration not working
A field 
To get useful answer you should show us at least the form…
Can I upload images? I’ve got the form down right now as I’m poking at things.
An image will not allow me to check HTML and JS code, nor to re-create the problem. Plus your form may be different from the image, as you change it now. So give URL instead.