>If you can't tell us what "specific setting" is really at the root cause of this error, then it is the UT's fault.

You're blaming me for something that I don't control and not even aware of. So far, others seem to believe that this is in regards to security. I can't confirm or help in that direction because I simply can't reproduce that behavior here. One thing for sure, there is a local setting that causes it. It is probably at the browser level but could also be related to a proxy, if applicable, or similar.