Webviews are not shown when running the browser app in the cloud

[chroberino]

Bug Description:

I am running a browser app of Theia blueprint in Google Cloud (see "Additional Information" section below for more details). Webview contents are not rendered here, instead I can see the only messages like:

Hmm. We’re having trouble finding that site.
We can’t connect to the server at 4abb51cd-e31c-5697-9c6e-2c7bc6783e68.webview.mydomain.tld

(As always, of course, it did work perfectly when running the browser app on my localhost.)

Steps to Reproduce:

1. Build browser app using an unmodified browser.Dockerfile and deploy output artefacts to cloud hosting
2. Open URL of cloud-hosted Theia browser app
3. Install "Jira and Bitbucket (Atlassian Labs)" extension (atlassian.atlascode)
4. Open command palette and pick "Atlassian: Open Welcome Page"

Additional Information

• Theia Version: 1.49.100 (reported by the "About" box)
• Platform: Google Cloud
• Cluster: Self-managed Kubernetes cluster
• Pod info: node:20-bullseye-slim | X86/64 | Balanced persistent disk
• Network info: google cloud dns