With your suggestion, I changed it to

$yesterday = [DateTime]::Today.ToString('M/d/yyyy HH:mm ')
$NotLoggedOut = Get-LoggedOnUser -ComputerName Pluto | Where-Object {$_.LogonTime -lt $yesterday}
$Script={param($Command); Write-Host $Command;  &cmd /c "$Command"}
$Command = Foreach ($User in $NotLoggedOut) {msg "$User.username Hello $User.Username You been logged in since $User.LogonTime"}
Invoke-Command -ComputerName Pluto -ScriptBlock $Script -ArgumentList $Command

Now it gives this error

msg : Invalid parameter(s)
At \UsersWhoHaveNotLoggedOut.ps1:56 char:46
+ $Command = Foreach ($User in $NotLoggedOut) {msg "$User.username Hello $User.Use ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (Invalid parameter(s):String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

Send a message to a user.
MSG {username | sessionname | sessionid | @filename | *}
    [/SERVER:servername] [/TIME:seconds] [/V] [/W] [message]
  username            Identifies the specified username.
  sessionname         The name of the session.
  sessionid           The ID of the session.
  @filename           Identifies a file containing a list of usernames,
                      sessionnames, and sessionids to send the message to.
  *                   Send message to all sessions on specified server.
  /SERVER:servername  server to contact (default is current).
  /TIME:seconds       Time delay to wait for receiver to acknowledge msg.
  /V                  Display information about actions being performed.
  /W                  Wait for response from user, useful with /V.
  message             Message to send.  If none specified, prompts for it
                      or reads from stdin.