This problem happens in Huawei devices. This GPS tracking app only tracks when the app is in foreground. Once in background, the app stops. Huawei requires you to explicitly allow the app working in background. To opt-in this option, go to Settings -> Protected App and select the FollowMee app (or System Service if you are running the stealth mode).
This problem also happens in some Xiaomi devices. To fix it, go to Device settings -> Additional settings -> Battery & performance -> Manage apps battery usage -> Power saving mode. Turn this setting off.
What should I do if the map page does not show up-to-date location?
Why does the tracker app not follow my configured track interval? I set it to 1 minute but the app only wakes up every 5 minutes.