With the deprecation of TLS 1.0 and 1.1, users of the Excel add-in may experience the following error:
Error connecting to CA Agile Central: The request was aborted: Could not create SSL/TLS secure channel.
or
Error connecting to CA Agile Central: The underlying connection was closed: An unexpected error occurred on a send
This is due to the WinHTTP protocol that Excel uses to communicate with our infrastructure to perform the query operations configured within the add-in. WinHTTP does not use strong security in its default configuration. If upgrading to the latest version (2.4.4 and above) is not an option, there may be an unsupported workaround: add registry settings to support this.
In our testing , we found it necessary to add the registry entries to the following locations:
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]
"SchUseStrongCrypto"=dword:00000001
Please be aware that modifying the registry carries some risks and it is best to have your Windows administrator perform the change if you do not feel comfortable working in the registry.