Flight Alerts on Airline Aircraft

I set up an email alert on an airline aircraft a few weeks ago. The aircraft is N294JB, a JetBlue E190. It can be tracked on FlightAware, but I have received no alerts on it whatsoever. Is it not possible to get alerts on airline tail numbers, or am I doing something wrong?

We only support alerts for the operating callsign at this time - airline and flight number for airlines, tail number for GA.