@Arif3: Sorry to hear that you're experiencing network issues on your Galaxy S20. Have you noticed if you're losing signal in a specific area/region, or is it persistent in all areas? Are you able to try another SIM card in the device to see if you notice an improvement? Similarly, can you try your current SIM in another compatible mobile, as this will help to determine if the issue lies with the phone or your network/SIM. In the meantime, as a basic troubleshooting step, please try pressing the Volume Down and Power buttons together until the phone restarts, as this will refresh the device and address any temporary issues that might be a contributing factor.
I am also facing network issues with my s20plus. Both my SIMs are having an issue in pulling the signals. I am unable to make or receive calls most of the times. When I am indoor, I need to connect to WiFi for better connectivity. But when I am not having WIFI, my mobile will go alien mode most of the times... I checked my signal by using a different mobile for the same SIM card and the signals are pretty fine and the browsing is awesome.. Signal is dropping very frequently on my s20plus.
Does this occur with all contacts, or a selective few? Is it in the same location, or does it occur in all places? Also, could you also test the receiver by dialling *#0283# > Select RCV Packet Loopback ON (or it may appear as Start : RCV_1stMic) > Say a few words as though you were on a call. If you're able to hear your own voice, it means your receiver is fine.
I'm getting same on s20 ultra. Wife has cheap hauwai which shows 2 bars to my zero. Both are on same EE network in cornwall. Also have S9 and S10 with same poor signal. Not great when cheap phone out does the flagships.