No Clone/Format HDD/install new Mac OS/Removing/Clearing Settings/Reinstalling is NO help.Same exact ID with every reinstall now in version 12 and 13.
Please do the following on BOTH Macs:
1. Open the TeamViewer application. 2. Click on TeamViewer on the top left corner. 3. Go to Preferences\Advanced and scroll to the bottom of the panel. 4. Once there, you will find the Un-install button which will allow you to do just that. Make sure you check the option “Also delete configuration files".
After that install TeamViewer again on both machines.