NEXUS card rejected at Canadian airport
I applied for and received a NEXUS card last autumn and it worked fine the first time I used it to fly into the U.S. from Canada. But this afternoon, when I flew back into YUL and when I inserted my card into the NEXUS kiosk, an error message popped up that said my card was "invalid" and that I should go through the normal line.
It wasn't a big deal because there was no wait, but I would like to know what the problem might have been for future reference. I haven't found anything online and can't think of what went wrong. I had an iris scan done by CBSA when I enrolled in the program precisely so I could use it at Canadian airports, and in the few months I've had the card I haven't changed my name or gotten a new passport.
If anyone can point me in the right direction, it'd be much appreciated!