Better Map overlay?

I get the same message
grafik

But according to the homepage off OWS Terrestris the WMS is not offered in all UTM zones (and only based on ERTS89 instead of WGS84)

So I projected my data into this one


grafik

and this works

So you would probably have to translate your data into WGS84 (EPSG:4326) which is the only globally valid one.