2amigos/yii2-file-upload-widget Where does SyntaxError: Unexpected end of input come from?

Question

JavaScript

Good day to all. Help to understand the issue of the YII2 widget.
I just recently started working with the wonderful FrameWork YII2, and I have difficulty installing widgets, because I don’t always understand what is needed for them to work. I recently encountered a problem with the widget 2amigos/yii2-file-upload-widget blueimp.github.io/jQuery-File-Upload/index.html (Basic Plus UI version) ... configured, uploading, everything is fine, the problem occurs when uploading file is completed... the script gives the error "Error SyntaxError: Unexpected token <", and in the debugger logs I see the following:

SyntaxError: Unexpected end of input at Object.parse (native) at jQuery.parseJSON ( admin.slider.loc/assets/ 5ce3ee4a/jquery.js:7522:14 ) at ajaxConvert (admin.slider.loc/assets/5ce3ee4a/jquery.js:7802:19 ) at done Full

controller and model taken from www.yiiframework.com/doc-2.0/guide-input-file-uplo... for 1 file upload .

As far as I understand, it swears at jQuery itself .... and the path to the library seemed strange to me, the fact is that I use the advanced version of the framework, and there the file structure is different ... please tell me what I'm doing wrong?