Get-RecipientPermission is unrecognized and Get-EXORecipientPermission executes with substantial delay when connected to exchange online using app authentication.

I have the same problem , no answer ?

@Daniel SENDAS

Unfortunately, no answers but... Looking for some other not related info I discovered that both Graph and EXO commands have some UNKNOWN :) limits that you can per second. So, there are two things I changed in my script:

• switched to 8 parallel streams only
• used a tricky collection to store data

So, my script looks like this now and produces 99% no-error results:

$mailboxes = Get-EXOMailbox -ResultSize Unlimited
$totalItems = $mailboxes.Count

$report = [System.Collections.Concurrent.ConcurrentBag[PSCustomObject]]::new()

$mailboxes | Foreach-Object -ThrottleLimit 6 -Parallel {
    function Get-FullAccessPermissions {
        # This function collects FullAccess rights
        param (
            [Parameter(Mandatory = $true)][string]$Mailbox
        )
    
        $result = Get-EXOMailboxPermission -Identity $Mailbox -ErrorAction SilentlyContinue | Where-Object { $_.AccessRights -match "FullAccess" -and $_.User -ne "NT AUTHORITY\SELF" } | Select-Object User
        return $($result.User)
    }

    function Get-SendAsPermissions {
        # This function collects SendAs rights
        param (
            [Parameter(Mandatory = $true)][string]$Mailbox
        )
    
        $result = Get-EXORecipientPermission -Identity $Mailbox -ErrorAction SilentlyContinue | Where-Object { $_.AccessRights -match "SendAs" -and $_.Trustee -ne "NT AUTHORITY\SELF" } | Select-Object Trustee
        return $($result.Trustee)
    }    

    function Get-SendOnBehalfPermissions {
        # This function collects SoB rights
        param (
            [Parameter(Mandatory = $true)][string]$Mailbox
        )
        try {
            $result = Get-EXOMailbox $Mailbox -Properties GrantSendOnBehalfTo | Select-Object -ExpandProperty GrantSendOnBehalfTo | Get-EXOMailbox -ErrorAction SilentlyContinue | Select-Object UserPrincipalName
            return $($result.UserPrincipalName)
        }
        catch {
            return $null
        }
    }

    $record = [PSCustomObject]@{
        "Mailbox"              = $_.UserPrincipalName
        "RecipientType"        = $_.RecipientType
        "RecipientTypeDetails" = $_.RecipientTypeDetails
        "FullAccess"           = (Get-FullAccessPermissions -Mailbox $_.UserPrincipalName) -join "; "
        "SendAs"               = (Get-SendAsPermissions -Mailbox $_.UserPrincipalName) -join "; "
        "SoB"                  = (Get-SendOnBehalfPermissions -Mailbox $_.UserPrincipalName) -join "; "
    }

    $collection = $using:report    
    $collection.TryAdd($record) | Out-Null

    Write-Progress "Processing mailboxes" -Status $_ -PercentComplete ($collection.Count / $using:totalItems * 100)  
}