VBA code to save a 2013 file opened with 2016

Good afternoon all,
I have an Excel file created in 2013. There are macros in it which save the file automatically when a button is pressed. When the file is open with 2016 and the button is pressed, the macro executes correctly with the exception of the save feature. A message "Cannot access Request Form". At first I just had 'ActiveWorkbook.Save' in the file and after searching online, tried 'ActiveWorkbook.SaveAs Filename:=...' with no luck. It is not a read only file. It only works with 2013. Any help would be appreciated.

Thank you,
Ken

The Request form is a purchase request form workbook. Eash sheet in the workbook represents a different purchase order number. The form opens fine in 2016 and the macros work, except for the part that should save the file, then excel 2016 leaves the cannot access when trying to save. I am fairly certain it has to do with 2016, because I have a different file with groups rows and the 2016 version will not let the user ungroup them, but that's another minor issue I need to solve.

Thank you for your help,
Ken