Microsoft has started blocking customers from installing the Windows 10 May 2019 Update on domain connected devices that use MIT Kerberos realms. Microsoft is still currently blocking a number of Windows devices with compatibility issues from receiving the May 2019 Feature Update. Microsoft advises all users to “not attempt to manually update using the Update now button or the Media Creation Tool”” until this issue has been resolved. The affected client and server platforms are listed in the table below
Source: version 1809/Windows Server 2019 and version 1803.”