If you are getting notifications in general but these are sometimes delayed or missed, this may be due to poor cellular coverage in the area where your alert zone is located.
The GPS device on the bus sends its position to the system multiple times per minute through the cellular network. If cellular connectivity is poor in the area where your zone is located, there is a delay in GPS messages getting through to the system. This will result in your notifications being delayed, and If the delay is more than ten minutes, the system suppresses the notification altogether, as there is no purpose in sending a notification that is late by ten minutes or more.
If this issue persists across multiple days, we suggest that you move your zone to a different spot on the map, where the cellular connectivity is known to be better.