Windows Server 2008 SP2 does not natively support SHA-2, Microsoft has released the KB4493730 servicing stack update. Starting on July 16, 2019 updates for the operating system will only be signed using SHA-1. Microsoft strongly recommends that you install this update by itself before installing any other updates. There is a known issue with this update that causes it to get stuck on the “Stage 2 of 2″” or “”Stage 3 of 3″” during the update process when installed.”
Source: https://www.bleepingcomputer.com/news/microsoft/windows-server-2008-requires-kb4493730-to-get-future-updates/