Livebook giving unreachable when attempting to attach

[davidtew]

Hi, I am hoping for advice.

For several months I have used a macbook pro on Monterey, running a phoenix instance locally with several Livebook instances simultaneously, all with 'runtime settings' set to "Runtime Type Attached Node name dtewdevserver@_". This works very well, thanks to you all.

Now I purchased another macbook, to act as a server, and so cloned my Monterey macbook to the new macbook pro running Ventura.

This means the phoenix app is identical.

I have done virtually nothing to the Ventura mac (except I have to run xcode-select --install to fix the error invalid active developer path ()

Phoenix runs fine on the Ventura; it connects externally via cloudflare too, all just as it does on the original Monterey macbook.

The Livebooks are also identical. But there is a problem: in the Ventura clone, the Livebooks won't attach to the local phoenix, giving Node :dtewdevserver@_ is unreachable.

I would be grateful for any ideas or pointers to information about this situation.

I suppose this is not a Livebook issue really; I am sorry that this is most likely my poor knowledge about macos (I have seen one other thread in this QA itself about problems attaching to fly.io (and on stackexchange), but to be honest the discussion there is over my head). But I have got this far with a few knowledgeable nudges in the right direction, so I am sure I can get the server up and running.

[josevalim]

To be clear, you are trying to connect to a node in the same machine? If so, what does iex --sname foo return to you? What is printed as the prompt?

[davidtew]

TL:DR

You shone a BEAM of light which I followed and could see what needed to be done.
Now Livebook is connecting to the local machine.
Thank you!

Just to complete your queries and so this thread...

So, yes, I am trying to connect to a node in the same machine as the Livebooks are.

As per your instructions, I applied iex --sname foo and I attach an image of the result.

Since you asked me 'what is printed as the prompt' , and as per screenshot we can see that the prompt shows as dtewdevserver@MacBook-Pro , I supposed I should try dtewdevserver@MacBook-Pro within Livebook to connect with (rather than dtewdevserver@_, which is what I have been doing in the original macbook). So now Livebook connects to the local machine. 😊

[davidtew]

Should I mark what I wrote as the answer?

[josevalim]

Yes! Glad it is all solved!