# Specifying credentials and connecting to Office 365 module
$Credential = Get-Credential
$Credential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $Username, $Password

Connect-MsolService -Credential $Credential

# Getting a list of tenant IDs (clients) used to connect to their environment
$Tenants = (Get-MsolPartnerContract)
$JobsInProgress = $null

$TenantsRemaining = 0 # Tickets every time a new tenant is being processed

# Running command against all tenants

# Keeping track of how long each tenant takes
$StopWatch = [System.Diagnostics.StopWatch]::StartNew()

ForEach ($Tenant in $Tenants) {
    # Get primary domain for the tenant
    $Domain = (Get-MsolDomain -TenantId $Tenant.TenantId.Guid `
            | Where-Object { `
                $_.Name -NotLike "*onmicrosoft.com" -and `
                $_.Name -NotLike "*microsoftonline.com" })[0].Name

    Start-Job -Name $Tenant.Name -ScriptBlock {
        $Domain = $args[1]
        $Credential = $args[2]

        # Authenticating to Exchange Online for the tenant
        $Session = New-PSSession `
            -ConfigurationName Microsoft.Exchange `
            -ConnectionUri https://outlook.office365.com/powershell-liveid?DelegatedOrg=$Domain `
            -Credential $Credential `
            -Authentication Basic `
            -AllowRedirection


        try {
            Import-PSSession $Session `
                -ErrorAction 'silentlycontinue' `
                -DisableNameChecking `
                | Out-Null

            $ExistingRule = Get-TransportRule | Where-Object { $_.Name -eq 'Block Microsoft License Verification' }

            # Remove existing rule
            if ($ExistingRule) {
                Remove-TransportRule $ExistingRule.Name -Confirm:$False
            }
            else {
                New-TransportRule `
                    -Name 'Block Microsoft License Verification' `
                    -SubjectContainsWords 'Microsoft License Verification' `
                    -DeleteMessage $True `
                    | Out-Null
            }

            Remove-PSSession $Session
        }
        catch {
            Write-Error $_.Exception.Message
        }
    } -ArgumentList @($Domain, $Credential)
}

# Waiting for jobs to finish
do {
    Get-Job | Where-Object State -eq 'Completed' | Remove-Job -Force
    $JobsInProgress = Get-Job

    $ElapsedSeconds = [math]::Round($StopWatch.Elapsed.TotalSeconds, 2)
    $TenantsRemaining = $JobsInProgress.Length

    Write-Output "Jobs have been running for $ElapsedSeconds seconds... $TenantsRemaining tenants remaining."

    Get-Job | Receive-Job # Check for errors

    # Removing failed jobs
    Get-Job | Where-Object State -ne 'Running' | Remove-Job -Force

    Start-Sleep -Seconds 10
} until ($JobsInProgress.Length -eq 0)

Get-PSSession | Remove-PSSession