Are you comfortable with editing macros? If so, add a debug line as follows. This is right at the beginning of the macro at around line 23 (after the headers):
Save the amended macro, then try clicking the 'Send to GSAK' button and see if you get a message in GSAK
| GSK |
Msgok msg=$_MacroParms |
Save the amended macro, then try clicking the 'Send to GSAK' button and see if you get a message in GSAK