Whya are we getting "Fill required Question" error on submit?

Hi there,

Form sometimes does not submit when error message comes up and says "needs to fill required questions".

But I can't find the questions that I missed.

I was testing the form, so I have to back and forth the questions with conditions. It may cause it to maifunctioning.

Once answer "Yes" to go to a questions and go back to the same question and try "No" this time, kind testing, so visited question may not be properly answered.

But bizarre thing is sometimes at the end, it doesn't submit, because it says " all required question must be answered", but I can not find the failed questions.

How can I make sure not to happen to the users? Any ideas?

I have just gone through your form and noted that you have setup conditions to hide required fields. This will cause the error since once the field is hidden and you have set it to required then the field is non filled causing the error. 

Its always recommended to setup fields you need to Hide/Show using conditions as un-required or use conditional logic to set field as un-required once its hidden.

Below is a guide on how to set field to required or Un-required using conditional logic.

https://www.jotform.com/help/367-How-to-Make-a-Field-Required-Based-on-User-s-Answer

Kindly do let us know if you need further assistance.