Onyx Boox M90 Touchscreen Doesn't Work At All
I have exactly the same problem.
It appeared after 3 months and I tried all what was mentioned already in the other replies.
Eventually, I ordered a new stylus from the European Boox reseller - but also the new stylus did not solve the problem.
Thus I am really desperate - since I bought the Boox M90 during a stay in the US in Summer and - there is no international warranty.
The reader is quite good - I had already a PocketBook pro 902 - the screen shows higher contrast (Pearl ink)
and also the reading of pdf's is great. Navigation is also quite ok and thoughtful.
But it doesn't help at all when the hardware is not reliable - already after 3 months ...