MAC OS 10.12.0

Hello, the x.y.0s are no longer available only the latest versions of x.y.LastVersion.

See if you can upgrade to 10.12, 10.13, or 10.14, see sys requirements...

https://support.apple.com/kb/sp742?locale=en_US

https://itunes.apple.com/us/app/macos-sierra/id1127487414?ls=1&mt=12

https://support.apple.com/kb/sp765?locale=en_US

https://itunes.apple.com/app/macos-high-sierra/id1246284741?mt=12

https://support.apple.com/kb/SP777?locale=en_US

https://itunes.apple.com/us/app/macos-mojave/id1398502828?mt=12

Any Mac that is capable of Sierra 10.12 is capable of High Sierra:

Get macOS High Sierra

Depending on the specs you may be able to run Mojave:

Upgrade to macOS Mojave - Official Apple Support