SVP Code -> no mp4 on Basic Encoder transcoding options

Hi, I'm Taurus.
SVP is installed on two Windows PCs.
Win7/64bit & Win10/64bit.
Everything is working nicely and smooth.
One exception:
On the Win10 machine we only get mkv, no mp4 output how hard we tried...
We need 1920x1080 50fps mp4 encoded with NvEnc at 24.8Mbs.
I managed that SVP Code accept the 1920x1080 resolution, but have not found a way
to mux into the mp4 container.
The NLE we are working on is not MKV compatible. That's why.
As a workaround we mux everything with mp4box, but this is one step to avoid.
The Win7 PC is muxing nicely to mp4.
I dont know what's different on both machines.
I compared the settings on both, but could not make my head on the differences...
Maybe just a little switch I've overseen.
If someone can give me some advise where to look, I will be forever grateful.
I just bought the Pro Version a few days ago and I must say it is worth every cent.
The GUI is a bit cumbersome and I'm missing some kind of presets for noobs.
(Not everyone knows about ffmpeg, mpv, avisynth, vapoursynth, lav and so on.
I'm a long time avisynth addicted, knowing all this framerate converting plugins and scripts...
But for my friend, who is using the NLE most of the times, this is almost chinese.
So bare with me and him.
If you need more Infos, just call...
#Taurus#