Adobe (Pro) Fill&Sign Fails with Unknown Error

Issue is Adobe Acrobat Pro – opening a PDF file – User could fill out but other people could not sign the document (PDF) within Adobe.

Error message when trying to sign the document after filling out the form: Fill & Sign – ‘The operation failed because Adobe Acrobat encountered an unknown error.’ – Yep that’s helpful – NOT!

Found link to help resolve this problem – not easily found however:

Link: https://community.adobe.com/t5/acrobat-reader-discussions/fill-sign-the-operation-failed-because-adobe-acrobat-encountered-an-unknown-error/td-p/9189189/page/2

Followed steps below to resolve:

Click on the “Protect” tool in Adobe Acrobat Pro DC.
Then at top of the application, click: “Remove Hidden Information”.
Click on the “Remove” button that shows up on the left side of the screen and you can watch as it removes “Metadata, Bookmarks, Comments and markups and Overlapping objects”.
Once this hidden info is removed click on “Close”.

Afterwards user is able to click on the “Fill & Sign” button and add signature.