When trying to install a PowerShell module I was getting this error... WARNING: Unable to resolve package source 'https://www.powershellgallery.com/api/v2/'. PackageManagement\Install-Package : No match was found for the specified search criteria and module name 'XXX'. Turns out it was a problem with the SecurityProtocol, fixed by entering [System.Net.ServicePointManager]::SecurityProtocol = [System.Net.SecurityProtocolType]::Tls12; SecurityProtocols I had in place before entering this command were... PS C:\WINDOWS\system32> [System.Net.ServicePointManager]::SecurityProtocol Ssl3, Tls Afterwards, I had PS C:\WINDOWS\system32> [System.Net.ServicePointManager]::SecurityProtocol Tls12