I got the same answer as you did. They did make some changes to the nginx server but ended up blocking access to the attachments entirely. I am looking at alternative options at the moment. I am reluctant to do anything that would impact the site speed in the future, and then for me not to remember what changes were made to the server and what to undo.
If they manage to come up with a solution let me know.
Cloudways tech support is going to have a look. If they solve it, I’ll let you know what they did.
I also have this issue, but with Cloudways (who also run apache and nginx) Attachments are visible on private documents when viewed through an incognito window. The AllowOverride is on for the apache server
I think this might be something you want to explore David, as if nginx fast service delivery is being used by hosts to deliver websites quickly, you don’t want your plugin to impact site speed because it has to be turned off.
I have let Cloudways tech support know and I’m awaiting their response regarding the impact on site speed.
