Go to the Block List tab along the bottom and make sure that you turn on the switch to "Allow Contacts."
You may have to do these further steps as well. Go to the settings tab in the bottom right and then tap on Call Settings. Make sure and set "Calls from saved contacts" to do nothing.
If you set "Calls from saved contacts" to do nothing it should ask if you want to give the app access to your contact list. If you say yes then it should whitelist them. I would try turning that setting off and then back on.
If that does not work I would try uninstalling and the reinstalling the app then trying the steps again.