媒体查找器小部件"不适用于关系类型文件附件"，如下所示:

'media finder widget' not working with relation type 'file attachment', like this:

public $attachOne = [
   'avatar' => 'System\Models\File'
];

尝试使用其他类型(例如:json)

try to use another type (for example: json)