We can't show MailTips right now

[vmjan02]

I have the below code and it is working all perfect. I don't understand it is completely ignores the code part

.SentOnBehalfOfName = "F.mum@xx.com"

and outlook shows "We can't show MailTips right now"

Any idea or solution as the below scrip is working all good and error free.

Sub Image()
'Application.Wait (Now + TimeValue("0:00:03"))
Sheets("Summary_").Select
    'Open a new mail item
    Dim outlookApp As Outlook.Application
    Set outlookApp = CreateObject("Outlook.Application")
    Dim OutMail As Outlook.MailItem
    Set OutMail = outlookApp.CreateItem(olmailItem)
    'Dim xPath As Range
    'Get its Word editor
    OutMail.Display
    xPath = Sheets("Reference").Range("a2")
    
   With OutMail
    .SentOnBehalfOfName = "F.mum@xx.com"
    .To = Sheets("Email").Range("C2").Value
    .CC = Sheets("Email").Range("C3").Value