Can't figure out why I receive a bad request

I'm using the radzen Upload component in this way

<RadzenUpload Multiple="true" Url="upload/multiple"
Style="margin-bottom: 20px;"
Progress=@(args => OnProgress(args))
Error=@(args => OnError(args))>

my startup.cs is here https://drive.google.com/file/d/1ay966w4JzcTi2gp9JASpbSvhZaHbe0xy/view?usp=sharing is complex but it contains all the necessary settings requested by radzen to be correctly executed.

when I try to upload any file, I receive a bad request

the response tab is empty.

I don't understand why but I can't even reach the UploadController. Where am I doing wrong?