the l2tp connection attempt failed because the security layer encountered a processing error during initial negotiations with the remote computer - Event 789
The Event Log will also log entries with error code 789, stating that the connection to the VPN failed.

Uninstall KB5009543   (it will come back) or get the "counter the break" from the list below

Windows 10: wusa /uninstall /kb:5009543  (THESE MAY FIX THE ISSUE TEMPORARILY)
Windows 11: wusa /uninstall /kb:5009566  (THESE MAY FIX THE ISSUE TEMPORARILY)
Windows Server 2012 R2: wusa /uninstall /kb:5009624  (THESE MAY FIX THE ISSUE TEMPORARILY)
Windows Server 2019: wusa /uninstall /kb:5009557  (THESE MAY FIX THE ISSUE TEMPORARILY)
Windows Server 2022: wusa /uninstall /kb:5009555  (THESE MAY FIX THE ISSUE TEMPORARILY)

;Windows Registry Editor Version 5.00

;[HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Rasman\Parameters]
;"ProhibitIpSec"=dword:00000001
; This will absolutely make things worse


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NONE OF THE ABOVE SOLVED THE PROBLEM GO HERE GET THE WINVER AND GET THE 64 DOWNLOAD
IT IS 100s of MBs !!!!
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https://www.catalog.update.microsoft.com/Search.aspx?q=%20KB5010793

My computer needed 20H2 (winver)
64bit (Windows+Pause/Break)

windows10.0-kb5010793-x64_3bae2e811e2712bd1678a1b8d448b71a8e8c6292.msu

List of fixes to counter the break from KB5009543
    Windows 11, version 21H1 (original release): KB5010795
    Windows Server 2022: KB5010796
    Windows 10, version 21H2: KB5010793
    Windows 10, version 21H1: KB5010793
    Windows 10, version 20H2, Windows Server, version 20H2: KB5010793
    Windows 10, version 20H1, Windows Server, version 20H1: KB5010793
    Windows 10, version 1909, Windows Server, version 1909: KB5010792
    Windows 10, version 1607, Windows Server 2016: KB5010790
    Windows 10, version 1507: KB5010789
    Windows 7 SP1: KB5010798
    Windows Server 2008 SP2: KB5010799

Updates for the following Windows versions are available only on Microsoft Update Catalog. For instructions, see the KB for your OS listed below:

    Windows 8.1, Windows Server 2012 R2: KB5010794
    Windows Server 2012: KB5010797