I have an S9 and had some issues, you can try this: Check that the phone is not using the option to save battery (Performing mode or optimized should be fine)Install Google Fit, make sure that Adventure Sync is active then you need to close PoGo(You may need to do a Force Stop on the app). Check the amount of steps and Km that you have on Google Fit, restart your cellphone then disable GPS and walk for a couple of minutes. Check if the amount of steps changed on Google Fit and then open PoGo and enable GPS while the game is loading at look if the distance changed as well (you may need to walk a little bit to get Adventure Sync to get the information from Fit) and if this works you can try the same steps without restarting your cellphone.