Thanks for that. I ran the command:
umbrel@umbrel:~$ wscat -c ws://localhost:3355
Connected (press CTRL+C to quit)
>
So...I think that's good...?
I am not familiar with Portainer or Tailscale, apologies. What I would suggest is to test that your relay is able to accept websocket connections at all prior to using with a client.
I have a section here where I am setting up a relay with auth, and test the connection with wscat.
https://rodbishop.npub.pro/post/52120fe7/
If all else fails open a GitHub issue with the devs. Utxo and Anthony are quite responsive
Discussion
Yes, it seems your Haven is running and available on localhost. So, then the question is, can your client (wherever it is running) access that localhost?
Ordinarily your client is not running on the same machine as your relay and so cannot access localhost, rather needs an IP address of some kind.