is the WAN ip address on the modem router a public IP or private? you can also try the DMZ

Wired connection has no issue? it might be caused by the wifi interference, you may try to change the channel to see whether it helps, or check firmware update

I cannot read... english would be more common here...

Minimum bandwidth so that it will not be too slow on that device

Do you still have internet access? ooh, if you reset it to factory default, you will not get internet until you configure it again, you may check whether computer get correct IP address from it and...

You set Client to LAN or LAN to LAN VPN on the MR6400? The status of the VPN Tunnel is connected or not? You need to check the IP address of the 3G/4G part on its web interface to see whether it is a...