unable to connect to VS and open code window

[hgong4316]

Does this occur consistently?
Repro steps:

Action: Resolver.resolve
Error type: 335
Error Message: Cannot connect to Jupyter Lab Terminal. Please try again.

Version: 1.4.5
OS: win32
OS Arch: x64
OS Release: 10.0.26100
Product: Visual Studio Code
Product Version: 1.108.0
Language: en
UTC time: Thu, 22 Jan 2026 16:27:05 GMT

Call Stack

extension.node.js:2:463316extension.node.js:2:463316
async u.checkForBadGateway extension.node.js:2:463197
async m.ensureIsConnectable extension.node.js:2:1770075
async m.getConnectionHub extension.node.js:2:1769221
extension.node.js:2:12855extension.node.js:2:12855

[Siglud]

• If you can't connect to a notebook, make sure that websocket communication is not disabled. For compute instance Jupyter functionality to work, web socket communication must be enabled. Make sure your network allows websocket connections to .instances.azureml.net and .instances.azureml.ms.

• When a compute instance is deployed in a workspace with a private endpoint, it can be accessed only from within virtual network. If you're using custom DNS or hosts file, add an entry for < instance-name >.< region >.instances.azureml.ms, with the private IP address of your workspace private endpoint.

Retrieve the status of Jupyter in your compute instance by running:

• https://-46802..instances.azureml.ms/ciapi/v1.0/services/jupyter/status OR
• https://..instances.azureml.ms:46802/ci-api/v1.0/services/jupyter/status
  If your kernel crashed and was restarted, run sudo journalctl -u jupyter to look at the Jupyter log and find out more details. If kernel issues persist, consider using a compute instance with more memory.

If you run into an expired token issue, sign out of Azure ML studio, sign back in, then restart the notebook kernel.