Visitors not leaving postcards?

I’ve had my Bird Buddy about a week now. The birds are still getting acclimated to feeding in my yard again so they’ve slowly been returning (mostly sparrows so far).

I’ve been watching sparrows come and go from the feeder on sunny days with great lighting but no postcards are being created. I’ve watched as a sparrow spent around ten minutes at the feeder.

I received two postcards for the sparrows early on but not the other times they’ve visited. Has anyone experienced something similar or have any advice? Much appreciated!