Your theme is throwing a JS error which is causing the JS validation on the registration page to fail – http://take.ms/f7ScL
Its caused by the theme using incorrect JS syntax that became a problem when WordPress update the jQuery library with version 4.5, we have some details here:
The support post ‘First Name Required Error (3)’ is closed to new replies.
Have a question about this support post? Create a new support post in our support forums and include a link to this existing support post so we can help you.
Support forum for Event Espresso 3 and Event Espresso 4.