Question UnityWebRequest ConnectionError in 2021 LTS but not 2020 LTS, WebGL

I'm running into a weird issue, where I call UnityWebRequest, and it succeeds in 2020 LTS, but not in 2021 LTS. This is on a WebGL build. In the Unity Editor, it works fine. I'm calling the exact same url under both versions. In 2021 LTS, I get result ConnectionError.

The server is a .NET 6.0 console application.

Anyone have any ideas where I can look into this more? Or is there a known issue with 2021 LTS WebGL builds?

 

Always the device / runtime / browser logs, obviously.

Networking, UnityWebRequest, WWW, Postman, curl, WebAPI, etc:

https://forum.unity.com/threads/using-unity-for-subscription-lists.1070663/#post-6910289

https://forum.unity.com/threads/unity-web-request-acting-stupid.1096396/#post-7060150

And setting up a proxy can be very helpful too, in order to compare traffic:

https://support.unity.com/hc/en-us/articles/115002917683-Using-Charles-Proxy-with-Unity

 

Ah, I can always count on Kurt-Dekker's copy and paste response to be at the ready. If it weren't so helpful, I would otherwise find it annoying.

 

Thanks, I try. I am always amending my copy/pasta stuff, plus often it gets hand-modified as I post it for a particular answer.

I am always open to suggestions for how to make it more useful, so don't be shy if you have ideas!

 

https://forum.unity.com/threads/htt...url-using-unity-2021-unitywebrequest.1343882/

This is actually exactly what's happening with my build. Has anyone else experienced this problem?