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 think the issue you mentioned was exactly same as the one reported here just a while ago
Here are the details how to fix it also.
Refer to this guide https://www.jotform.com/help/137-How-to-Limit-Submissions-in-a-Form
If you set the limit on Expiration Date to be lower than current date -- that error will pop-up as a reminder.
Just removed the Expiration Date value in the Form Limits -- or set it up to a future date instead.
Hope this help. Inform us if issue remains.