Why can't I make phone calls/access contacts on my Galaxy S8+?

[AC Question]

Whenever I try to make a phone call or open my contacts, an error message pops up that says, "Contacts has stopped." I've tried clearing cached data and factory resetting my phone, but the problem still persists. What can I do now?

 

[B. Diddy]

Welcome to Android Central! Does this happen in Safe Mode as well? https://support.t-mobile.com/docs/DOC-34283