How to debug Web GUI on WR21 transport

I am not able to access the GUI over the web. It works to a very limited extent, bringing up the login prompt and kind of a skeleton of the GUI, but no real functionality.
When I connect over the local LAN, in the Interfaces box, the Ethernet 0 and Ethernet 1 indicators are both green, while the Cellular indicator is red. However, I do have an IP address, am able to reach it with Traceroute, and can get the limited login mentioned above.
I appreciate any guidance on ways to further test the functionality
Thank you


this could be due to the connection speed over the cellular

have you tried to SSH / Telnet over the cellular connection and does that work fully but slow?