Windows 7 was not originally shipped with support for SHA-2 signature validation. Since SHA-1 is considered less safe some Ananda components for windows are signed using SHA-2.
This means that some older versions of Windows 7 might fail to validate these components and fail the Ananda installation and/or login flows.
This can be fixed by downloading and installing the following Microsoft provided (and signed) hot fixes:
https://download.wireguard.com/windows-toolchain/distfiles/Windows6.1-KB2921916-x64.msu
https://www.catalog.update.microsoft.com/search.aspx?q=kb4474419
Please note that restart might be required after installing these hot fixes