Simple-Ajax-Uploader | Javascript file upload plugin with progress bar support | File Upload library

I know that you already checked that:

could be file permission issues, but after giving the uploaded files including their directory) all possible permissions, they are still 404 Not Found

But maybe the problem is with ownership of the file, according to this S.O answer What's the meaning of this error message in error log?:

Bad permission or ownership can also trigger this error. I have resolved it by changing ownership of my application directory. It was owned by root before.

And here again with the same error you get in your log file:

https://alexantop.wordpress.com/2013/05/07/caught-race-condition-abuser/

with the same solution:

Change the files ownership to “username”.

Can you check the ownership of the folder and try to change it to www-data or some user that can be accessible from internet.

Hope it helps!

It turns out that typeRoots is only used for loading declarations for globally defined identifiers (hence why it worked when I removed the import statement). For imported modules you need to use the paths property in tsconfig.json: