Well, we added this answer test on 15th July 2018, so it is quite possible your server does not yet have this!
https://github.com/maths/moodle-qtype_stack/commit/0a11cfb24e0b21f124a949c0d97bdadbb91d1c6a
Chris
Well, we added this answer test on 15th July 2018, so it is quite possible your server does not yet have this!
https://github.com/maths/moodle-qtype_stack/commit/0a11cfb24e0b21f124a949c0d97bdadbb91d1c6a
Chris