Failing on port / access control

[valhuber]

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I have been using Codespaces for some time. It is failing today, with my web app reporting:

Fetch API cannot load https://valhuber-fantastic-computing-machine-4654xrvwrx2qv97-5656.githubpreview.dev/api/Category?include=&page%5Blimit%5D=25&page%5Bnumber%5D=1&page%5Boffset%5D=0&page%5Bsize%5D=25&sort=CategoryName due to access control checks.

To recreate:

1. Use this repo
2. The .devcontainer is supposed to create a port - it does, but it is not public as it usually is, per "postAttachCommand": "/bin/bash .devcontainer/setup.sh"
3. Use Run Config 3a. Logic: No Security
4. Open the Browser as offered
5. Click Categories -- observe error above

Repeated runs usually fail, but work maybe 1 of 8 times. Not sure, but I believe making the port public (by hand) was required, but I am unable to reproduce a successful scenario.