Can't sign my pdf

[lirong5C19]

My Adobe Reader cannot sign. When "Fill and Sign" is turned on, the "Sign" button is always gray, even if I select the space or area I want to sign (the "Sign" button is gray). I tried everything I knew and I couldn't change it.

[Amal.]

Hi lirong

Hope you are doing well and sorry for the trouble. As described you are unable to use the fill and sign as the button is not active (Grey)

Is this a behavior with a particular PDF file or with all the PDFs? Please try with a different PDF file and check.

Also try to repair the installation of  the Adobe Acrobat Reader DC (Win Only) from the help menu. Go to Help > Repair Installation and reboot the computer once. 

If it still doesn't work, please try to reset the Acrobat Preferences as described in the help page - https://community.adobe.com/t5/acrobat/how-to-reset-acrobat-preference-settings-to-default/td-p/4792...

You may also try to create a new test  user profile with full admin rights in Windows or enable the root account in Mac and try using the application there and check.

Regards

Amal