Why this is not Working?

[Shafty]

                            Dim MyRegExp As RegExp
                            Set MyRegExp = New RegExp
                            With MyRegExp
                                .Pattern = "(?<=Your message wasn't delivered to )(.*)(?= because)"
                                Cells.SpecialCells(xlCellTypeLastCell).Offset(1, -1).Value = MyRegExp.Execute(Returned_Mail.Body)
                            End With

 

[Fluff]

Duplicate How to make this regex work in Excel?

Please do not post the same question multiple times. All clarifications, follow-ups, and bumps should be posted back to the original thread.
Per forum rules, posts of a duplicate nature will be locked or deleted (rule 12 here: Forum Rules).