Thank you for your reply.
Adding the script in the HTML made the JSFiddle example work :)
Also, for the issue inside our app, it was crashing before when my datapoints were using number format instead of Date objects.
I was using 1743480000000 instead of new Date(2025, 03, 1).
Is it always recommended to use Date objects here? Or is there some property on X Axis that I could use to make this work?