Fillable pdf forms not allowing to sign

I did check PDF form of your last edited form in PDF editor and you seems to have added signature field correctly. You should be able to sign in PDF form without any problem.

Are you able to input in PDF form field? Is the signature field being displayed? Which PDF viewer you are using where you are not able to sign in field? I would suggest you to please use Adobe Acrobat Reader or Foxit software and get back to us if the issue persists. 

I would suggest you to please share a screenshot of the issue and we will take a look. The following guide should help you how to upload image in forum post: https://www.jotform.com/help/438-How-to-Post-Screenshots-to-Our-Support-Forum 

We will wait for your response.