Here’s how to do it; keep in mind if this is a multi-node environment it will need to be done on each node running QVS. Also, stopping the QlikView Server service will kick out any active users, so may need to plan accordingly.
Stop the QlikView Server service
Save a copy of the Settings.ini file before editing!
Edit the QlikView Server settings.ini file (you may need administrative priveledges to do this. By default the file is here: C:\programdata\QlikTech\QlikViewServer\Settings.ini)
Add the following line inside of the [Settings 7] section: AllowMacroFunctionsInExpressions=1