Thanks again @KellyHutchins I was of course working in a scene with EPSG:25833 refsys and have to add the EPSG code into the URL parameters. Can not share the scene but these parameters are fine:
&viewpoint=cam:-30000,6733000,400,25833;0,90 (being X,Y,Z,EPSG code, direction/azimuth, camera angle)
Many thanks for prompt reply's - much appreciated 🙂
best
Pål Herman/pH