Hello,
Another issue with this challenge may be that areas where there were a large queue many may be going to those places, and thus the queues are clearing out quickly. The error message you received does mean that the queue was empty at the location you were at, so you would need to change to a location that has a queue still, but we really don’t know where those are, as staff hasn’t said anything, and so we’re left with bouncing around the map.
This isn’t really a lag issue, per se, but more of an issue with us not being told where there’s still a large queue and targeting those areas. Someone recently suggested a heatmap for challenges like this, but I doubt it’ll be put in place this time around.