Set-DistributionGroup DGName -MemberJoinRestriction Closed

It worked for several other boxes with no problem, but I have one box that will not accept the command:

C:\Windows\system32>Set-DistributionGroup Software.Support -MemberJoinRestriction Closed
Members can't remove themselves from security groups. Please set the group to Closed for requests to leave.
    + CategoryInfo          : NotSpecified: (:) [Set-DistributionGroup], RecipientTaskException
    + FullyQualifiedErrorId : [Server=DTimeStamp=9/8/2020 7
   :50:26 PM] [FailureCategory=Cmdlet-RecipientTaskException] Microsoft.Exchange.Management.RecipientTasks.S
  etDistributionGroup
    + PSComputerName