Cannot Sign Digital Signature in Reader (Red Ribbon shows but can't Sign)

I made a PDF signable PDF form and did the following: 

1. Created a digital signature block
2. Ensured that the security settings allow the document to be signed
3. Saved as Extended PDF to enable additional Reader features

The PDF has been deployed on a Web Server and when a user renders it in the browser the majority of the form fields are filled out. At this point, the intent is to allow the user to digitally sign the document; however, the red ribbon to sign shows, but nothing happens when you click the field.