Hi Isdoo,
It’s hard for me to give you actionable advice here without more information about the settings of your form and the checkbox field in question. For example, are you using any conditional logic? Which version of WordPress and jQuery are you running? Etc.
Have you tried submitting the form with your JavaScript console open and error logging on? If not can you please try and let me know what errors you see? We have a guide on how to do this here: https://calderaforms.com/2016/05/wordpress-debug-logging/
Once you report back with the errors, we can get to solving your problem immediately. If you find nothing, please still let us know. This means we need to take a closer look at your form configurations, or you may have found a bug, in which case I want to make sure I report it and put it in our product update calendar ASAP.
