The map can not be accessed when your smartphone is directly connected to the dashcam's Wi-Fi because, at that time, your smartphone can't be connected to the internet to access the map server.
If you save a recording into the Internal memory and watch the video there, you can see the map and GPS details (speed, location) provided that your smartphone is connected to the internet at that time.
The GPS details (speed and location) are visible when you access the dashcam recordings over the Cloud provided that you have allowed the BlackVue app to access the GPS data of your dashcam.
If the speed stamp displays as " -- km/h " or " -- mph" on the recordings, it means that the GPS was not working at the time of recording. If the GPS issue persists, refer to the GPS issue troubleshooting article.