Onlyoffice Error, unable to load editor

I’m having some problems with the Onlyoffice app. It won’t load the document and throws an error.

I’ve installed the document server docker on a different machine than my Nextcloud server. The document server shows the green status page. I have the document server behind a reverse proxy so I can do HTTPS easier.

In the settings page I put in the “Document Editing Service address” field. The page accepts it. In the file manager I can create a docx and open it. The editor loads and then presents an unknown error. In the console it loaded a resource from the document server, but the resource wasn’t from the domain but was the document server’s HTTP IP address. I think this is where the error is coming from.

Blocked loading mixed active content “”

How do I fix this?

I’m on NC v14.0.4.2 and have whatever the most recent version of the Onlyoffice app is.