Microsoft’s KB4577062 update for Windows 10 versions 1903 and 1909 will cause compatibility issues. Microsoft says the issue is caused by the Windows 10 Setup Dynamic Update being unable to download required updates. Microsoft advises customers to work around this known issue by re-enabling HTTP access to the Internet to the update. The company is working to address this issue with a fix to be available in an upcoming Windows 10 release. Users have also seen this warning when trying to upgrade to Windows 10, version 2004 (aka May 2020 Update)
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-upgrades-blocked-after-installing-kb4577062/