Function Break-InheritanceSubWebs($WebURL)
{
    Try{
    #Set up the context
    $ctx = New-Object Microsoft.SharePoint.Client.ClientContext($WebURL)
    Write-host "Connected to $WebURL" -ForegroundColor Green
    $ctx.Credentials = $Credentials

    $Web = $ctx.Web
    $ctx.Load($web)
    $ctx.Load($web.Webs) 
    $ctx.ExecuteQuery()
    Invoke-LoadMethod -Object $web -PropertyName "HasUniqueRoleAssignments"
    $ctx.ExecuteQuery()

    if ($web.HasUniqueRoleAssignments)
    {
        write-host -f yellow "$($web.title) has unique permissions"
    }else
    {
        write-host -f red "$($web.title) does not have unique permissions"
        #Break Permission inheritance of the Web - use existing groups from parent
        $Web.BreakRoleInheritance($True, $False)
        $Ctx.executeQuery()
        write-host -f yellow "Permission Broken for site $($SiteURL)"
    }

    #Iterate through each subsite in the current web
    foreach ($Subweb in $web.Webs)
    {
        #Call the function recursively to process all subsites underneaththe current web
        Break-InheritanceSubWebs($SubWeb.URL)
    }
    }catch
    {
        write-host -f Red "199 Error ! unable to break permissions for site - $($WebURL)" $_.Exception.Message
    }
}