Variable Output in Email

$listmanagers = Get-ADUser -Filter * -SearchBase "OU=Non Employees,OU=Users,OU=Accounts,DC=Contoso,DC=com" -Properties Manager| where-object { $_.manager -ne $null} | %{(Get-AdUser $_.Manager)} | select-object -Unique
ForEach ($listmanager in $listmanagers)
{
 
$contractemp = Get-ADUser -Filter { manager -eq $listmanager} -SearchBase "OU=Non Employees,OU=Users,OU=Accounts,DC=Contoso,DC=com" -Properties Manager 
$managername = get-aduser $listmanager | select-object name
 
$body ="    Dear $managername,"
Send-Mailmessage -smtpServer $smtpServer -from $from -to $recipient -subject $subject -body $body -bodyasHTML

If I run that query, everything works as expected, but when the email is sent, the manager name looks like this:
Dear @{name=Manager Name},

What do I need to change, so that it reads

Dear Manager Name,

Thanks,
J