Hello @gergo,
I discovered the cause of the issue, “Failed to fetch”.
From my host (windows 10 machine) I was calling the front end with http://localhost:5066/ when CANONICAL_URL: ‘http://127.0.0.1:5066’.
When I tried with http://127.0.0.1:5066, it worked!
I will continue discovering Speckle.
Regards,
Alberto