Amazon S3 Storage

This is a new install and then I added one plugin. So I’m not sure if my problem is related to the plugin or the Kanboard application.

The plugin is Amazon S3 Storage. When I attach a document to a task it appears to work but when I try to view there is nothing there. When I download the attached file, there is no content.

What I was expecting to happen is when I attach a document then it is sent to S3 storage and always viewable on Kanboard from the task. Using S3 Browser I can see that nothing went to the S3 bucket. I setup the S3 credentials in Integrations, Amazon S3 Storage on Kanboard.

Any ideas? Is there a different method to test the Amazon S3 Storage plugin to see if it is working correctly? Thanks.

Application version: 1.2.11
PHP version: 7.1.31
PHP SAPI: cgi-fcgi
HTTP Client: cURL
OS version: Linux 3.10.0-957.10.1.el7.x86_64
Database driver: mysql
Database version: 10.2.26-MariaDB
Browser: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.132 Safari/537.36

I’m not familiar with this plugin and I don’t have a S3 account to test it, so I’ll need your help to debug.
I assume the plugin talks directly to amazon. Do you have any proxy on your network that kanboard should be passing through to get to Amazon?
If you enable php error logging, does any error is logged when you upload and try to view attached files?