As per GuitarDemon's post above, I switched to the Google dialler and made it my default app, and the problem is fixed for me. I have a Samsung Galaxy Note 9 and have had this issue since that update at the end of 2020 (driving me crazy in the process).
Samsung needs to fix this, can't believe I have to use the google dialler to bypass this glitch!!
Well google dialler only fixed it for one day for me - then my Note 9 reverted back to the same problem - cannot receive incoming calls (ie it doesn't connect, people can't hear me unless I put the loud speaker on and off)
SAMSUNG PLEASE FIX THIS ISSUE - ITS BEEN MONTHS!
The latest software update for my Note 9 (that came through in the last 2 weeks) seems to have fixed the issue for me. I will keep you posted if anything changes. Hope the latest software update for the Galaxy series works for everyone!
I didn't have this problem until very recently and the workaround of switching the speaker on and off fixes it.
Did Samsung ever fix this issue only for it return?