Please refer to: https://support.microsoft.com/en-us/help/4472027
Essentially, in August 2019 Microsoft will start to sign all of the updates released for Server 2008 (Vista) with SHA2.
You need to install these updates so that the OS will be able to deal with them.
First install the Servicing Stack update (KB4493730) before installing the main update (KB4474419).