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.
It appears that your form has a Unique Question set in the preferences. When a unique question is set, you will only be able to accept unique entries based on that unique question. This means that when a user inputs the same data on the unique question, the form will not accept it and they will get the error "Sorry one entry is allowed."
You currently have the "Curso" field set as the unique question, which means duplicate data in the "Curso" field will not be accepted.
To resolve this issue, please set the Unique Question to "No Check" instead.
For more information on Unique Questions, please check out this guide: How to set Form Limits Based on a Unique Question.
Thanks for the reply .I will check how it works now