Why doesn't the thankyou appear on the screen after a form is submitted? All I see is a message to create a jotform.

It seems you have the deleted the form https://www.jotform.us/form/51606412688155   that have the issue.

Please restore the deleted form first on your My Forms list so we can properly investigate the issue you reported.

User guide: https://www.jotform.com/help/134-How-to-Restore-Deleted-Forms

We will wait for your updated response.