Puppet->E1001: how to show Icons?

Hi,

I have an E1001 e-ink display and have a dashboard with custom:html-template-card which uses icons. The icons are showing fine in the dashboard per se but puppet doesnt seem to pick them up or doesn’t like them.
Is there a good way to implement icons (preferably mdi) so that they show on the e-ink display? Does anybody know where the exact issue is?

Thanks a bunch for your support!