Yes last 3 days I had to make multiple outgoing calls to fixed line numbers and noticed that when dial the number it shows dialling but no ring sound either in the ear speaker or loudspeaker. I ended call, dial again sometime can sometimes cannot. Did not reboot just left it for a few minutes then call again can ring already. It gives me the impression that there's no line when it happens eg like you don't have SIM card in the phone and you call out. My signal was full and using redmi note 8t.
