Samsung Galaxy S21 5G no mobile data ,physical sim card and esim not working, signal reception very low in malta Europe, or poor mobile network signal.
Hi @Members_MLTMMG. Do you have a case or a cover on your phone? Please remove the SIM card and give the contacts a rub then reinsert it. Also, please test your phone in Safe Mode. To do this, hold the 'Power/Bixby' button and the 'Volume Down' button, both together for a few seconds and then long press on Power off on the screen. This will change to Safe Mode so tap on that to restart. This will disable third party apps and if your phone is fine during this, indicates that an app may be causing the issue and I recommend deleting apps one by one until you find the culprit. Let me know how you get on.