what to do when message multiple submission is not allowed on this form?

Hi,

You have to adjust the settings or remove it, please checkthe following guides:

http://www.jotform.com/help/137-How-to-Limit-Submissions-in-a-Form

http://www.jotform.com/help/223-How-to-set-Form-Limits-Based-on-a-Unique-Question

http://www.jotform.com/help/64-How-to-Set-Unique-Submissions-on-a-Form

Thank you!