cannot capture extra buttons for Razer Deathadder v2 X

[StG999]

the app cannot capture when i click the additional buttons on my mouse. it can only capture the primary, secondary and middle (scroll) button out of which the first two are non-configurable.
i cannot connect my mouse via bluetooth (it keeps loading then stops), so i use it via its 2.4GHz dongle. it has 4 more buttons but none are sensed by the app.

i've tried the pre-defined button 4 & 5 too but nothing is happening.