Hi,
the link for the wcf data services 5.6 is not working: http://go.microsoft.com/fwlink/?LinkId=320724
It is required for Sharepoint 2019 as a prerequisite - please restore urgently!
(seems that happened already also in 2019 --> http://social.msdn.microsoft.com/Forums/en-US/SP2016/thread/c5c50c72-eb96-4057-9baf-331b9644334a/)
