Outlook VBA Macro not modifying email - vba

Question

I am running the following script on the event that I receive an email from a specific address with a specific subject. The goal is to tag an email with a hyperlink that will be useful for the recipient of said email to have in the original message's body.
Option Explicit
Sub Megatron(MyMail As MailItem)
Dim objOL As Outlook.Application
Dim objNS As Outlook.NameSpace
Dim strID As String
Dim strLink As String
Dim strNewText As String
Dim strLinkText As String
'On Error Resume Next
Set objOL = Application
strID = MyMail.EntryID
Set MyMail = Application.Session.GetItemFromID(strID)
If Not MyMail Is Nothing Then
Set objNS = objOL.Session
MyMail.BodyFormat = olFormatHTML
If MyMail.BodyFormat = olFormatHTML Then
MsgBox ("set to html")
End If
strLink = "http://www.example.com"
strLinkText = "Click on this Example!"
strNewText = "<p><a href=" & Chr(34) & strLink & _
Chr(34) & ">" & strLinkText & "</a></p>"
MyMail.HTMLBody = Replace(MyMail.HTMLBody, "</body>", _
strNewText, 1, 1, vbTextCompare)
MyMail.Save
MsgBox ("Hyperlink appended!")
Else
MsgBox ("Failure!")
End If
End Sub
While I get the message box telling me that the proper event occurred it appears that no actual changes are made (or are not being saved properly?).
This is the first work I have done with any kind of programming. I've gone through some tutorials for VB specifically, but I am very new to this. Any help/guidance is much appreciated!

Answer 1

This is a classic case of needing to use Option Explicit to require explicit variable declarations. Use this, since you are learning VBA. Also avoid the habit of using On Error Resume Next as this ignores all error handling.
You might not realize this but you are referring to your mail item in the following ways:
MyMail
objItem
objMsg
objMail
Note that the following two commands
objMsg.HTMLBody
objMail.Save
are performed on non-existent objects.
Remove the above three extra references:
Sub Megatron(MyMail As MailItem)
Dim objOL As Outlook.Application
Dim objNS As Outlook.NameSpace
Dim objItem As Object
Dim strID As String
Dim strLink As String
Dim strNewText As String
Dim strLinkText As String
strLink = "http://www.example.com"
strLinkText = "Click on this Example!"
strNewText = "<p><a href=" & Chr(34) & strLink & _
Chr(34) & ">" & strLinkText & "</a></p>"
MyMail.HTMLBody = Replace(MyMail.HTMLBody, "</body>", _
strNewText, 1, 1, vbTextCompare)
MyMail.Save
end Sub
You also don't need the cleanup either.