USB tethering internet does not work

I'm trying to set up USB tethering, cell phone is also detected. Internet unfortunately does not work. I followed these instructions exactly:
What did I miss?
Anybody got any ideas?

Have you configured already USB-tethering connecting Smartphone to PC?

The first attempt at this should start with default settings, install the tethering driver (usually kmod-usb-net-rndis) then change the existing WAN network's physical interface to be the phone. Do not create new interfaces unless you're doing something fancy-- which should only be attempted after knowing the basic setup does work.

When you do create new interfaces keep the names short and all lowercase (LuCI very unhelpfully upcases them, creating confusion). The kernel has a limit of 15 characters for an interface name, which includes the "br-" that OpenWrt will internally add if the interface is a bridge.

I see no packets received and no DHCP address obtained, suggesting a problem with the link to the phone. Make sure that USB tethering is enabled in the phone's settings.