JupyterHub client keeps trying to reconnect to kernel

I have followed the instructions for installing the littlest on digitalocean several times. When I attempt to create a new python3 notebook for the first time, my client connecting / status indicator flashes every one second, as if it can’t reach the server. I get a websocket error in the browser console. I see people saying that they fixed this by downgrading particular packages like tornado, however I don’t know how to get into the python environment for this install. E.g. if I log into the server and do a ‘pip3 list’ I don’t even see the tornado package, presumably because I’m not in the right env. Thanks.

Hi. Could you show us the error messages from your browser console?

I tore down the vm but this is the text of the message: " [

Websocket client closes with "unexpected reserved bits 0x60 …

But that looks to me like a red herring that’s really indicative of something simpler, like maybe a port needs to be opened?