Script not sending email with function

I am trying to make an automated script that once a month will send an email to our companys managers about externals working in their departments about their accounts expiring.

I have made this, but when it has directreports in the top it wont send any emails, when i change them to manager i also have to change the to address but then i get the correct e-mail at least.

Get-ADUser -Filter * -SearchBase '' -Properties Manager,DirectReports,EmailAddress,Displayname  | ForEach {
    $ManagerName = $_.Displayname
    $body = @()
    If ($_.directreports) {

        $managerEmailAddress = $_.EmailAddress

        $_.directreports | ForEach {

            $userDetails = Get-ADUser -Filter * -SearchBase '' -Properties AccountExpirationDate

            If ( $userDetails.AccountExpirationDate ) {

                If (($userDetails.AccountExpirationDate -lt (Get-Date).AddDays(30)) -and 
                ($userDetails.AccountExpirationDate -ge (Get-Date))) {

                    $sendEmail = $true

                    $props = [ordered]@{
                        'Account Expiration Date'=$userDetails.AccountExpirationDate

                    $body += New-Object PsObject -Property $props




    If ($sendEmail) {

        $body = $body | Out-String

        Send-MailMessage -From '' -To $managerEmailAddress -Subject 'Account Expiration Report' -Body $body -SmtpServer 'smtp server'


    $sendEmail = $false


Your Send-MailMessage function look like the are missing parameters necessary for it to work correctly, I would recommend that you take a look at this: Send-MailMessage (Microsoft.PowerShell.Utility) - PowerShell | Microsoft Docs