I was using Like Gate because I wanted readers of a specific article to make a little effort to like the article but discovered a couple of weeks later that none of the forms on my site displayed a Submit button. After going through my list of plugins, deactivating them one by one, I determined that Like Gate was the problem. I am using Easy Contact Forms on my site and Like Gate seems to have a conflict.
If Like Gate is activated then any form on my website does not display a Submit button. This is for all forms that I used Easy Contact Forms plugin to create, which I have 3 forms. These forms have nothing to do with Like Gate. When I deactivated Like Gate the Submit Buttons on all Easy Contact Forms reappeared. I also have 2 other testimonial form generator plugins on my site, WP Customer Reviews and Testimonial Basics. All of these forms were not affected by Like Gate but they were also wrapped in a Spoiler tag. I hope that helps you narrow down the problem. FYI my website is: http://www.sunkissvillas.com