Could be the same issue as here:
Thanks Anton, was there a solution posted there, as I don't really read russian.....
Google Translate?
Try the updated app from here: https://www.traccar.org/forums/topic/android-11/page/2/#post-64701
Working great for 3 days except won't start after the device reboot.
Hi,
We have various samsung phones tablets feeding into a traccar instance, we get user reports that on random moments the mobile application stops sending updates (thus devices offline).
If the app is stopped (Server status button to "off" ) and restarted it works again.
Is there any reason this may happen ?