Macro that runs for every sheet stops working

Hi

I have a macro that runs through every sheet (no matter how many or few) of a workbook. It attaches each relevent worksheet to the relevent email within the sheet.

This macro worked fine, up untill a few months ago. The macro runs and attaches most sheets as normal, but it the email address in cell A1 which it looks up is no longer recognised

The bit of the code is

    For Each sh In ActiveWorkbook.Worksheets
        If sh.Range("A1").Value Like "?*@?*.?*" Then

I have looked into this and cannot find out to why the email addresses are not picked up, each is a valid address with @ in and all vary in length.

Why would the macor work as normal and then not recognise the email addresses? No error messege is returned, the macro just runs till its normal end.

Thank You