Cannot upload file

I receive this error every time after uploading. I tried image & GH files. Tried disabling ad-blocker, as well as in Edge and Chrome.

The request to AMZN S3 looks OK though.

Hi -
I copied your image and am testing the upload here.
That seems to work fine from my end.

If you are in China, use a proxy.

Somehow I can upload files on other Discourse-based sites. The issue may be related to Amazon S3 as I would investigate a little bit more.