Membership plugin: Members can't download protected files

Hello,

I'm having difficulty with the Membership plugin.

What I'm trying to do: protect a file.csv, a CSV document, so only Members can download it.

What I've done:

1) Added example.com/documents to the Actual Download URL field in the Membership plugin's Edit Options page.

2) Added example.com/obfuscated to the Masked Download URL field in the Membership plugin's Edit Options page.

3) Created a protected group called membersonly in the Membership plugin's Edit Options page.

4) Used the standard Wordpress media uploader to upload file.csv to example.com/documents

5) Used the standard Wordpress media uploader to set file.csv to be part of the membersonly protected group

6) Copy/pasted the URL from the Wordpress media uploaded, example.com/documents/file.csv into a blog post and published it.

6) Added the protected download group membersonly to my Member level in the Edit Levels page of the Membership plugin

7) Created a user with a Member account, and logged in with it in a different browser to the one I'm logged in as an admin.

Logged in as a Member and viewing the blog post in question, I'm seeing the link example.com/obfuscated/file.csv.

So far, so good.

But when I click it, I get the Membership plugin's No Access image.

Any ideas where I went wrong?