Send Outlook email, from Excel, from specified account - excel

Question

I'm trying to send an email from Outlook with an attached .pdf file via Excel 365.
The routine works up to a point, but I have to select the email account manually from the open email otherwise it sends from the default account.
I am using objMail.SendUsingAccount = "billing#anEmailAccount.co.uk" but I still have to manually select the email account (name has been changed for security reasons).
Sub Email_Sheet_Click()
Dim objOutlook As Object
Dim objMail As Object
Dim signature As String
Dim PDF_FileName As String
Dim oWb As Workbook
Set oWb = ActiveWorkbook
'PDF File name
'Change accordingly....
PDF_FileName = Range("S12").Value
ActiveSheet.ExportAsFixedFormat Type:=xlTypePDF, FileName:= _
PDF_FileName, Quality:=xlQualityStandard, IncludeDocProperties _
:=True, IgnorePrintAreas:=False, OpenAfterPublish:=False
Set objOutlook = CreateObject("Outlook.Application")
Set objMail = objOutlook.CreateItem(0)
objMail.SendUsingAccount = "billing#AnEmailAccount.co.uk"
With objMail
.Display
End With
signature = objMail.HTMLbody
With objMail
.To = ActiveSheet.Range("M5")
.Cc = ActiveSheet.Range("A3")
.Subject = "Invoice for Daycare Fees"
.HTMLbody = "<font face=" & Chr(34) & "Calibri" & Chr(34) & " size=" & Chr(34) & 4 & Chr(34) & ">" & "Hello," & "<br> <br>" & "Invoice attached " & "<br> <br>" & "Regards," & "<br> <br>" & "Playgroup Billing" & "</font>"
.Attachments.Add PDF_FileName
.Save
.Display
End With
Set objOutlook = Nothing
Set objMail = Nothing
End Sub

Answer 1

objMail.SendUsingAccount expects an Accounts object as value. As seen in the microsoft documentation for MailItem.SendUsingAccount, you can enumerate the accounts collection and sent the email from the correct one - like this:
Dim oAccount As Outlook.account
For Each oAccount In Application.Session.Accounts
If oAccount.AccountType = olPop3 Then
Set oMail.SendUsingAccount = oAccount
objMail.Send
End If
Next
PS: See here for code that turns an SMTP address into an Account object.