This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms when building an app with visual studio

I had a hard time with this too. Go to HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\Lsa. Under a subkey you should see FipsAlgorithmPolicy. DELETE this registry entry and restart visual studio.

REF: https://blogs.iis.net/webtopics/parser-error-message-this-implementation-is-not-part-of-the-windows-platform-fips-validated-cryptographic-algorithms-when-net-page-has-debug-true

You can fix this by adding <enforceFIPSPolicy enabled="false"/> under the runtime section in the .config files of:

• MSBuild (example path: C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\MSBuild\15.0\Bin\MSBuild.exe.config)
• Visual Studio (example path: C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\devenv.exe.config)

My answer was to change the registry key from 1 to 0 here:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\fipsalgorithmpolicy