I am running a Rocket.Chat server of my own and everything works fine with almost all mobile device clients (official 3.5.0) using it. So GCM and gateway (gateway.rocket.chat) work as should and notifications are showing correctly.
Except one phone that has LineageOS 16 flashed is not showing Rocket.Chat notifications although every other aspect do work with the app.
is this a known issue with LineageOS 16? If not how could I find out what is going wrong? So howto fix it or is it even possible?
I did try to search but did not find any relevant information about this issue yet.