From iOS14, there is a new item called "Accuracy location information" for setting location information for apps.
When "accurate location information" is OFF, information in the range of 1km to a maximum of 20km will be passed to the application side with respect to the actual acquisition point, and it may be recognized as a location away from the actual location. There is.
In this case, even if you are in the stampable area, the app cannot determine the detailed location, so please use the "accurate location information" in the ON state.
Settings ＞ Privacy ＞ Location services ＞ "Admin" or "KING OF TIME" ＞ Accurate location: ON
