".send" command creates an error on one computer but not another

I have VBA code that has been working flawlessly for year. Now all of a sudden I am getting an error:
send error code.PNG
Run-Time error '-2147467259 (80004005)':

Outlook does not recognize one or more names.

When I select debug, .send is highlighted. I put the same workbook on another computer and everything runs fine with no errors.

Set OutApp = CreateObject("Outlook.Application")
        OutApp.Session.Logon
        Set OutMail = OutApp.CreateItem(0)
        With OutMail
        
        .To = ActiveSheet.Range("Q59").Value
        .Cc = ActiveSheet.Range("Q60").Value
        .Subject = ActiveSheet.Range("Q61").Value
        .HTMLBody = ActiveSheet.Range("P62").Value & ",<br><br>" & _
         ActiveSheet.Range("P67").Value & _
         ActiveSheet.Range("R67").Value & "<br>" & _
         "<font color=""#FF0000""><strong><br>" & ActiveSheet.Range("P99").Value & "</font></strong><br><br>" & _
        "Regards," & "<br><br>" & "The " & ActiveSheet.Range("P19").Value & " Support Team<br><br>"
   

       .Attachments.Add pdfName
       .Attachments.Add ManualForm

        .HTMLBody = .HTMLBody & logo & vbCr & vbCr & vbCr & ManEntGoals
        
        .Send
        End With

Any Ideas!!!

EDIT: I found a solution that does not make sense, but it works. By simply adding .Display a line before .Send the VBA code does not fail. I was thinking it might be a speed issue where the VBA code is runing too fast. So I added a delay statement just before the .Send. I added: Application.Wait Now + TimeSerial(0, 0, 5) which delays the running of the VBA code by 5 seconds. But it still fails when it reaches .Send. The one thing I find interesting is that I use the .Send command about 3 times to send emails to specific people, but they don't fail.

I don't feel comfortable with the .Display command fixing the issue. Any one know why that works.