Johnny G

I have a 2016 Audi A6 and last night whilst driving the "fuel tank malfunction indicator" appeared saying please refuel immediately and it had "0" mile left in the fuel tank. It went from 125 miles to 0 and just wondering what the issue maybe and do not want to have to fork out 100s to take to a main dealer if it is something I can sort out. Anyone else have this type of issue and appreciate some advice ?