Solved
The mathcad express prime licence activation
It doesnt want to activate it for the free 30 day trial.
- "Opening Mathcad Express Free Trial for the First Time": https://www.youtube.com/watch?v=GXlwfOPglk8
- "30 trial days of PTC Mathcad Prime - how to activate": https://community.ptc.com/t5/PTC-Education-Forum/30-trial-days-of-PTC-Mathcad-Prime-how-to-activate/td-p/702263