I’m using a teracube 2e with a bluetooth headset. When someone call I can hear the sound in my ear but the phone screen does not show me who is calling. I want to see who is calling me.
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Going by the topic title about the missing pop-up, you could check the following settings for a start …
Settings - Apps and notifications - See all … apps - Phone - Notifications
Settings - Apps and notifications - See all … apps - Phone - Advanced - Display over other Apps
Settings - Apps and notifications - Notifications - Notifications on lockscreen