Help in pick up a file using File chooser + Transfer

I want to upload different kind of files to an server, and I’m trying to use ‘File Chooser +Transfer’, but is not working, It open the file chooser but it’s not catching the file, I’m receving an error mesage. To sent to the server, first I need catch the file, than I need to change it to base64. If you did something like this, or if you know how to do it, it will help me alot, because the examples that I’ve seen wasn’t helpful.

Seeing the error message would probably be helpful. An additional option aside from the FileChooser plugin, although the default styling is not great, is to use plain old <input type="file"> to get the file.