As other posts have suggested, everyone I call hears an echo. I just purchased my Samsung S21 Ultra less than a week ago and its already having this persistent issue.
Fixes I've attempted:
I've reset in safe mode. This fixes it for ~2 hours. I'm not going to restart my phone 7 times a day so that's not a fix.
I've reset Bixby to factory settings. That didn't work either. Even if it did, I wouldn't call that a fix because I find Bixby to be wholly irritating and prefer to keep it off (persistently would turn on while using Google Maps preventing me from seeing directions).
I've ensured all apps are up to date and functioning.
Bluetooth is off, no other device should be interfering.
Please suggest a fix. I'd prefer to not have to exchange my phone.
1) The issue persists in speaker mode and not speaker mode.
2) Tried turning it off and on multiple times
3) Even with the volume all the way down, they still hear themselves. Also that's not really a solution as the Speaker mode is a completely standard phone function. If phones from 2014 could do speaker without echo, I don't see why my brand new device from 2021 is facing issues.
I've just recently started having this issue, but hopefully it won't come back like yours did after only a couple of hours. I tried all of the fixes, but the only thing that worked was rebooting in safe mode and then turning safe mode off. I really hope it will last for a long time. I've had the phone for about a year and only started experiencing this in the last few weeks. Wish me luck.