Please try the following methods to resolve the problem.
1) Restart the app.
2) If you are using Wi-Fi, turn it off and switch to 4G/5G/LTE.
3) Customers using LTE lines may have limited network speed set by the carrier. Check if the line is not restricted.
4) Adjust the graphics quality by tapping on the Gear icon > Game Settings on the Map screen.
Image Quality: Clarity of the on-screen appearance
Frame Rate: Smoothness of the on-screen animation
※For Android devices: if you have moved the app to an SD card, please move it back to the main device.