Download all SSRS reports via PS script error

[nenea-nelu]

While trying to download all SSRS reports from Win 2012R2 Running SSRS Reporting Services Version 12.0.6433.1, PSVersion 5.1 by using the script documented here:
https://social.msdn.microsoft.com/Forums/windowshardware/en-US/131338e2-06af-41ad-845f-cbbbde8429cc/issue-after-migrating-sql-server-reporting-services-from-2016-to-2017?forum=sqlreportingservices
and same on Stackoverflow.com: https://stackoverflow.com/questions/46783093/download-all-ssrs-reports
I'm getting the error below:

Failed to retrieve items in '/': Exception calling "ListChildren" with "2" argument(s): "System.Web.Services.Protocols.SoapException: The operation you are attempting
requires a secure connection (HTTPS). ---> Microsoft.ReportingServices.Diagnostics.Utilities.SecureConnectionRequiredException: The operation you are attempting
requires a secure connection (HTTPS).
at Microsoft.ReportingServices.WebServer.RsSoapExtension.EnsureHttpsLevel(SoapMessage message)
at Microsoft.ReportingServices.WebServer.RsSoapExtension.ProcessMessage(SoapMessage message)
at System.Web.Services.Protocols.SoapMessage.RunExtensions(SoapExtension[] extensions, Boolean throwOnException)
at System.Web.Services.Protocols.SoapServerProtocol.ReadParameters()
at System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()"
At C:\Program Files\WindowsPowerShell\Modules\ReportingServicesTools\0.0.7.5\Functions\CatalogItems\Out-RsFolderContent.ps1:84 char:9

This is the section of the code from line 84 mentioned above:
#region Retrieving content from Report Server
try
{
$itemType = $Proxy.GetItemType($item)
}
catch
{
throw (New-Object System.Exception("Failed to retrieve item type of '$item' from proxy: .Exception.Message)", $.Exception))
}

Does anyone have any idea how to overcome this error?