Prevent sign in for guest users

I am looking to disable all options to sign in and also to prohibit the use of Adobe Document Cloud. 

I have followed this community article but have not been successful in preventing sign in to Acrobat Reader.

HKLM\SOFTWARE\WOW6432Node\Policies\Adobe\Acrobat Reader\DC\FeatureLockDown\cServices

DWORD "bUpdater", Value = "0"