I have a question regarding the speed limit sign on the dashboard. It stopped working?

What is your question?

I have a question regarding the speed limit sign on the dashboard. It stopped working? It just shows a line of dots across but no speed limit. I realize it will not display sometimes on a rural or some roads but it is not working on major roads and highways. It stopped working in a couple days ago. I cannot figure out how to get it working again. There is nothing in my owners manual. Can you help Me? Thank you. 

How long has your 2017 Chevrolet Corvette had this problem?

a week