Echo on recipient side on S21 only in speakerphone mode

[dmo]

I have a brand new Galaxy S21 and when I am speaking to someone on the phone, if the phone is in speakerphone mode, the person I am calling hears an echo of themselves. I do have a phone case (Speigen liquid crystal case) that is on the phone. Is the case the reason? 

Any help is appreciated, I do like to use speaker mode quite a bit.

[texaninmichigan]

Thanks @Mark555  This seems to have helped.  @Steveuk I also implemented your solution.  Thanks to you both. 

[texaninmichigan]

@LW50 Thanks, I also did this.  Combined with the two other things, I finally don't have an echo!  

[Dot7869]

@Mark555 I've done as you suggested, now I'm waiting for someone to call me to test it. Thank you.

[Tpallot]

Thank you, @Mark555! My husband's phone was causing everyone to hear an echo and his friends were calling my phone to talk to him! Turning off video call effects solved the problem. I'm with you - I don't understand why, but I am grateful. Thanks! 

[Sohvajedi]

Thanks, Mark. I've lived with this problem a couple of years now and never bothered finding some kind of permanent solution, just asked people calling me back, that helped most times. It seems this IS a permanent solution,  so thanks again. 

-Marko