Users getting erroneous errors upon submission

Can you review my form to see if there are any strange set-up things that might cause occassional errors for users? I still get an issue about once a week where a user reports that they fill out the form just fine, and then when trying to Preview Answers, they get warnings about errors that are actually filled out correctly. Users keep saying the same thing over and over, so I know something buggy is happening. I'd like to resolve this if possible, especially since this is a relatively simple form.

Thank you!

Hello SunbridgeInstitute,

I'm sorry for the trouble caused to you.

I did test your form and I am not able to replicate the issue you are having. I was able to click on the preview button successfully and the answers were previewed successfully. What error message do you get when the preview button is clicked? I would suggest you to please share a screenshot of the error message and we will take a look. The following guide should help you how to upload image in forum post:  http://www.jotform.com/answers/277033

We will wait for your response.

Thank you!