Microsoft Outlook Proxy Server's Security Certificate (Error Code 80000000)

This requires advanced configuration of the Windows Operating System. If you are not comfortable performing such configuration you should contact your system administrator.

Microsoft Outlook

There is a problem with the proxy server's security certificate. Outlook is unable to connect to the proxy server . (Error Code 80000000).

You may also receive the following error when trying to setup the out of office replies in Microsoft Outlook.

“Your automatic reply settings cannot be displayed because the server is currently unavailable. Try again later.”

This error occurs because a component of AbacusLaw by CARET requires TLS 1.2 communication.

To fix, find the following registry key:

64 bit Windows Operating System:

1. [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp]
   • “DefaultSecureProtocols”=dword:00000a00

32 bit Windows Operating System:

1. [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings\WinHttp]
   • “DefaultSecureProtocols”=dword:00000a00
   • Set the “DefaultSecureProtocols” DWORD accordingly:
   • 0x00000080 Enable TLS 1.0 by default
   • 0x00000200 Enable TLS 1.1 by default
   • 0x00000800 Enable TLS 1.2 by default

The registry editor uses the last 3 digits of the hex key.

This Microsoft Knowledgebase articles outlines the purpose and use of the “DefaultSecureProtocols” registry key. Link

Microsoft provides an “Easy Fix” utility located at the bottom of the knowledgebase article linked above.