Use developer tools in your browser to find hidden controls which are invalid or required, and are causing the submit button to remain disabled.
- Open your form in Test Mode or using the Share URL. Fill it out and attempt to click Submit/Continue. If Submit/Continue remains disabled, continue to step 2.
- Open your browser developer tools. This varies by OS and browser, but on a PC you can use the keyboard shortcut Ctrl-Shift-i.
- In Elements/Inspector tab of developer tools, search for all instances of s-invalid. This will take you to the HTML of all the controls which are in invalid state.
- You can generally get the name, <cname>, of the control from that HTML.