S2 Member PHP API Constants not working

I can’t get any s2 constants to work whatsoever…
Is there something obvious or a common solution that I can try?
Even things like:
<?php echo S2MEMBER_VERSION; ?>
Don’t work…
Any help/pointers would be most appreciated!

Hello, sorry to ask again, but I’m under a bit of pressure with this… Has anyone ever come across the API Constants not working?? Is it something simple as a setting that needs turning on? I’ve tried using the [s2Get constant="S2MEMBER_VERSION" /] shortcode on a normal page and that doesn’t work either.

Okay, apologies for any confusion caused… It turns out that our hosting company WPEngine turns off API integration by default, I have enabled the API access and guess what - everything works as expected!