Multisite shouldn’t require different configuration, but it could be that some detail of your configuration is causing URL rewriting to fail for Doc attachments.
As a test, could you try the following:
1. Open the file wp-content/plugins/buddypress-docs/includes/attachments.php
2. Find the line that says $fn = $_GET['bp-attachment']
(should be around line 64)
3. Change it to: $fn = basename( $_GET['bp-attachment'] );
Could you also share more information about your configuration?
– Is this a newish WordPress Multisite installation, or is it a conversion from WPMU?
– When uploading a file to a blog post, what does the URL of the attachment look like? Is it example.com/files/2016/05/foo.jpg, or is it example.com/wp-content/uploads/2016/05/foo.jpg?
– Are you using any domain mapping plugins?
– What is your fileserver software? (Apache, Nginx, etc)
Thanks!