This happened with no apparent "provocation" from my part but my phone would'nt let me place calls 😮 😮 😮
When i try to dial a number, it says its calling, and just disconnects 😮 (not even humming sound that we normally hear at the start of any call or when dialling) and the funniest part is..its placing the call via GPRS 😮 😮 The "G" flashes while trying to place call, then it crosses the "G" out, and disconnects. (I should mention here, that incoming calls were fine at this time)
It set itself right after a reboot.
PS: BTW, i'm on 3.16