OpenVidu Classroom - Can publish but can't subscribe

@micael.gallego just finished deploying through this guide with all the defaults except the public url and the secret and the exact same behavior occurs, as shown below:

Tested with another computer and both can publish video but none can see the others video. Clean ubuntu server, clean installation. The IceConnectionState keeps changing to “disconnected” after a few seconds.

I would really love your help on this, since it seems it’s not a local network problem anymore.

EDIT:
And on the same note, the dashboard test also fails, as shown below:

Kind regards,
Leonardo Freire