Refresh not working on tablet (connected to Vera Edge)

i am trying aplication on my wall mounted tablet (android 8, external power) connected to Vera Edge. its looking great but refreshing widget not working.
It looks like the refhres works only few second - then just turning the screen off and on will help - state of widget are resfreshing.
any ideas where the problem is? do I have a faulty tablet because for example on my mobile it seems to work well?

@HanzP does it say that it is “connected” all the time to Vera in Platforms screen?
Also, please submit debug logs from Support screen after widgets stop refreshing.