First, please note that the dashcam WiFi does not support an internet connection, so it is normal to show it as "Connected without Internet" as per below.
While if you use iPhone or iPad and find the live video black, please disable the VIOFO APP from accessing cellular data (choose " WLAN " instead of " WLAN & Cellular Data ”) as below; If the issue persists, please turn on "Airplane Mode" on your phone directly.
If you use Android phones and can not access the app and menu successfully, please turn on the VPN in the "VIOFO" app as below; In case the issue persists, please also turn off the VPN programs on your phone. You can also try to turn off cellular data if the issue persitss.
There is another situation with Android phones if you have WLAN assistant and have ticked "Stay connected", as the camera WIFI does not support an internet connection, so when you access the VIOFO APP, there will be a popup "Can‘t connect to the internet" as phone WIFI tend to connect to your old devices first, please choose "No thanks", otherwise, you may not access the VIOFO APP；
Or you can just not tick "Stay connected" in "WLAN assistant".