Not prompting for Signature

I found this on another thread and resolved it.

When you select the "This document requires signatures" checkbox (which appears when you initially select Tools > Prepare Form), it sets it up to be used with the Adobe Sign e-signature service. If you didn't do this the first time that you selected Tools > Prepare Form, then you can select: More > Convert to Adobe Sign Form while you're in form editing mode.

Note that users will be able to use the Fill & Sign feature with a regular Acroform, so if you don't intend to use the Adobe Sign service, then you can leave it as-is and users will be able to place a hand-drawn signature anywhere they like, unless you add a digital signature field. 

What is your Acrobat and version? What is your OS and version?

Can you share a sample file of your form? If not, can you create a dummy form exposing the issue?