Fix ResourceUnavailable error when try to install PowerShell module via Install-Module cmdlet

If you try to install PowerShell module via Install-Module cmdlet, e.g.:

Install-Module -Name SharePointPnPPowerShellOnline

you may get the following error:

WARNING: Source Location 'https://www.powershellgallery.com/api/v2/package/SharePointPnPPowerShellOnline/3.20.2004' is not valid.
PackageManagement\Install-Package : Package 'SharePointPnPPowerShellOnline' failed to download.
     + CategoryInfo          : ResourceUnavailable: (C:\Users\Develo...20.2004.0.nupkg:String) [Install-Package], Exception
     + FullyQualifiedErrorId : PackageFailedInstallOrDownload,Microsoft.PowerShell.PackageManagement.Cmdlets.InstallPackage

In order to fix it run the following command in your PowerShell session:

[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

After that run Install-Module again – error should disappear.