The request was aborted: Could not create SSL/TLS secure channel for nuget push command

I am currently looking into using Octopus for our deployments. I'm trying to push the latest .nupkg file to our Octopus server as follows.

NuGet.exe push outputfolder\My.nupkg -ApiKey myapikey  -Source https://myproject.octopus.app/nuget/packages

However I'm getting the following error.

The request was aborted: Could not create SSL/TLS secure channel.

I've never seen this error before. What causes this error and how do I fix it?

UPDATE

I've installed the latest version of nuget.exe and this has removed the error message. However I'm now being prompted to enter my username and password when I upload the package to the Octopus server. How do I pass these in via my script?

I am seeing this when I run my script from the commandline.

Pushing MyPackage.nupkg to https://MyProject.octopus.app/nuget/packages...PUT https://MyProject.octopus.app/nuget/packages/Please provide credentials for https://MyProject.octopus.app/nuget/packagesUsername: