Question samsung a53 call waiting hangs up on both calls

[k72]

I have a Samsung Galaxy A53 5G. When a call comes in while I'm already on a call, it doesn't matter whether I answer it, decline it, or don't even touch my phone, once an action is selected, or once it times out, both calls are disconnected.
So let's say I'm talking to Mom. The Dr calls, and I ignore it and keep talking to Mom. After so many rings, the Dr call stops ringing. Then the call with Mom disconnects.

How do I fix this? I talked with Samsung support and have tried clearing the phone cache, safe mode, and resetting. Resetting worked for a few hours. I tried keeping the phone as stock as possible, sticking with the Samsung dialer and launcher, but within hours it was back to disconnecting. They are sending me to a repair place, but I figure they'll also tell me to reset (not sure how that works if they choose to take the phone - I guess I'm out of a phone for a while?).
Any ideas?

 

[B. Diddy]

Have you also discussed this with your carrier? Call Waiting is a carrier feature, so it might be something on their end.

 

[k72]

Have you also discussed this with your carrier? Call Waiting is a carrier feature, so it might be something on their end.

You were right! Turns out there was one minor (or not so minor) difference on the APN settings. I added a new profile with the updated APN and it fixed it. Thank you for the help!