Get-ExecutionPolicy

Set-ExecutionPolicy Unrestricted
Set-ExecutionPolicy Restricted

Install powershell 7 from powershell 5 : 
iex "& { $(irm https://aka.ms/install-powershell.ps1) } -UseMSI"


foreach ($u in $users)
{
Write-Host $u.Name -ForegroundColor Green
$cal = Get-MailboxFolderStatistics $u.Identity -FolderScope Calendar | Where-Object {$_.Name -in @("Agenda", "Calendar", "Calendrier", "Kalender")}

foreach ($c in $cal)
{
Write-Output $c.Name
}

}