What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
I'm sorry for the trouble caused to you.
The reason why you see this error message is because you have enabled the "Validate Image" property of your upload question. Since you are only allowing the user to upload the "PDF" file, it is not required to enable the "Validate Image" property. Please check the screenshot below:
"Validate Image" property should not be in ON status and clicking on it again to disable it should solve your problem.
Hope this helps.
Do get back to us if you have any questions.