Kodi stuck to 1080p on Nvidia Shield

This is my first post on the Kodi forum.

I installed Kodi version 17 on my Nvidia Shield, hooked it up to my LG OLED55E6 4K HDR TV and do NOT get 4K: I don’t even have the option to change my screen rez in Kodi, it’s just not available. I can’t even play regular 1080p, it just won’t start.

(I used VLAN player on the Shield too and with that I can play 4K clips and movies, so I don’t think it’s a hardware thingie).

Does anybody have any advice or tips?

Greetz from Holland,
Eric