Unable to Answer iPhone calls on iMac after Catalina Update

Prior to Catalina, I had no issues answering calls on my iMac or transferring ongoing calls from my iPhone to my iMac. After the update, incoming calls will ring on the iMac, but when I click Answer, the connection fails. My iPhone does recognize the iMac as a viable source for audio. (Press Audio button, choices are: iPhone, Speaker, iMac.) If I try to transfer from iPhone to iMac, the phone indicates audio is transferred to the iMac, but it does not actually transfer; instead the call audio ceases on the iPhone and no audio begins on the iMac.

I have tried restarting both devices. I confirmed both are on the same wifi network. My phone is set to Allow Calls on Other Devices, Allow calls on iMac. Both are signed in to the same iCloud account.

What's the fix?