First, make sure your location preferences/settings are turned ON in both your device AND the app you are currently using.
Next, uncheck the box for Wi-Fi and mobile network to determine your location. This will force the device to use GPS to determine location.
If you are still having problems checking in when you are at a particular location, it can be due to several factors. We use your device's location detection technology to determine where you are - this involves the use of cell network towers, GPS, and/or Wi-Fi to figure out the location of a device. If GPS is unavailable on the device for whatever reason (turned off, no connection, etc), the geolocation lookup falls back to cell tower triangulation, which is not as accurate.
Due to network issues, poor cell service, buildings or other physical barriers, the location detection may be inaccurate and we won't be able to correctly determine your location. If this happens when you are at or near the check-in location, we encourage you to follow the steps above in bold, try adjusting your physical proximity to the check-in location and try again. The closer you are to the venue you're checking in to, the better!