Avrios will show you suspicious fuel bills, which are bills that contradict the data in Avrios. If e.g. a refueling with gas has been assigned to a diesel vehicle, this refueling is declared suspicious and you can investigate it further.
Which case represents your situation?
The fuel card is assigned to the wrong vehicle
Click on the error message "Susceptible fueling" and then click the "Assign All" option.
Vehicle was actually refueled incorrectly
Locate the vehicle as quickly as possible and make sure nobody uses this vehicle before fixing the problem.