I'm using this (https://github.com/Gurgen/SignalR-.net-core-android-client) library for signalR connection on Android. It's working great on API 24 and newer APIs. But older devices, it's throwing handshake exception.
I tried to trust all certificates (I know it's not safe) for under API 24 devices but it doesnt work.
I think it's about SSL, but i didn't know how can run on old devices.