"Venus OS Large" link in VRM fails with "Could not connect to the GX" – Node-RED works locally

DIY
, , , ,
1

Device: Cerbo GX
Firmware: v3.75 (build 20260624163305), Image type: Large

Clicking “Venus OS Large” in VRM (portal and app) to open the Node-RED editor consistently fails with:
“Could not connect to the GX to download the requested resource. Check your network settings or switch to a different connection and try again.”

This happens on multiple devices/browsers and both locally and remotely, so it’s not a client-side network issue.

Troubleshooting done so far:

  • Rebooted the Cerbo GX multiple times – no change
  • Confirmed Node-RED service is running fine (svstat shows “up”)
  • Confirmed Node-RED responds correctly on localhost:1880 (curl returns HTTP 200 with the full editor page)
  • Found and fixed a missing nginx site-enabled symlink for the Node-RED reverse proxy (sites-available/node-red wasn’t linked into sites-enabled) – after fixing this, Node-RED is reachable locally via https://:1881 without issue
  • Confirmed the remote support ssh-tunnel process is running normally
  • “Remote Console” via VRM works perfectly, both before and after the nginx fix
  • Only the “Venus OS Large”/Node-RED link in VRM itself keeps failing, even after the nginx fix and several reboots

This points to the problem being in VRM’s server-side tunnel/routing specifically for the Node-RED link, rather than on the GX device itself.

Has anyone seen this and found a fix (other than a full factory reset)? I found a couple of similar threads here but no root cause was ever identified. Happy to share more logs if useful.

Thanks!

4

Do you have any devices configured in the modbus system settings on the GX?
Does the V1 console also work remotely?

5

Thanks for looking into this!

Modbus TCP is disabled (checked via dbus: Settings/Services/Modbus = 0), and I don’t have any Modbus RTU devices connected either.

Regarding the V1 console – could you clarify what you mean exactly? The only related toggle I could find on the device itself is Settings > General > Display & Appearance > User interface (Classic UI / New UI), but that only affects the on-device touchscreen GUI style, not what I understand as the VRM remote console rendering. Is there a specific link/URL in VRM you mean, or something else?

6

I had a similar issue. I didn’t investigate the cause but resetting Node Red resolved the issue. My flows were preserved too.

7

done that, combined with restarting inbetween toggeling, but no change