Build 14936.1000 truecaller showing unknown error while i m trying to set live caller id. Or setting-system-phone-chhose default apps is not giving option to choose truecaller
provide the feedback to the developer, it might help him with future support of redstone. What you should do now is reinstall the app , perform a soft reset and check whether the issue is resolved.
As you are on experimental insider builds, such glitches are very common and if they do not resolve you may wither have to wait for a new build or an app update in future.