CORS Error when Sending POST requests to Express Backend

[kirupa]

Are you running into this issue by any chance?

Early preview of public ports!

Found the problem! Thanks so much for helping us identify it. In short, one of our proxies is removing CORS headers (e.g. Access-Control-Allow-Origin) in the HTTP response for the browser’s OPTIONS request (aka “preflight”, which are used for POST requests). I haven’t found a good workaround yet, but we’ll follow up in the bug you filed (thank you!). Hopefully this is something we can resolve shortly. EDIT: I updated the bug title and added repro steps, will now follow up with our infra teams …