Location services with high accuracy locating method is mandatory for driver app to operate properly. It is intended to ensure better location accuracy and avoid wrong track issues caused by pure GPS or mobile network signal.
In case a driver sees a notification "For better accuracy, please turn on both GPS and WiFi/Cellular location services" he/she has to go to "Location services" on the device and enable "High accuracy" option in Location mode.
The steps may differ depending on the device and platform.
Consult the post on Phone notifications settings for drivers to get new jobs and How to keep driver app running in the background for further details on driver app settings.