The only case when you could be receiving approximate coordinates is when these are GSM coordinates, rather than GPS ones. This means that Monimoto was not able to catch enough satellite signal to determine the exact location,  so it was forced to use different technology to determine it.

What's the reason for the inaccurate coordinates?

If your Monimoto is already installed in a Motorcycle or other vehicle - please check if it's thinner end is facing outwards rather than inwards, or towards the ground. Incorrect installation might be the reason causing the poor signal. Please see correct installation instructions here.

Another reason could be that your Monimoto is indoors (GPS signal does not work properly when the receiving device is indoors).