In version "2017.12.09.07" I added extraction of MP4 links.
So, you can select exactly same links which are available on your PC.
If MP4 links will work smooth for you but HLS not then this mean that you have problem with gstreamer on your image or with drivers and you should report problem to VU+.
You can simple check if this is a problem with gstreamer or with drivers.
Install ffmpeg to you set-top-box then restart E2 and allow IPTVPlayer to install exteplayer3.
Then use exteplayer3 movie player (it does not depend on gstreamer libraries).
If the playback will not be smooth with exteplayer3 too then it will mean that the problem is in drivers and you should report the problem to VU+.
Manny services use HLS streams, so you should do this for your own good.