How to access Tomcat 8 admin gui from different host?

I followed this excellent article about putting Apache in front of Tomcat, acting as a reverse proxy:

https://www.digitalocean.com/community/tutorials/how-to-encrypt-tomcat-8-connections-with-apache-or-nginx-on-ubuntu-16-04

How can you access the admin gui from a remote machine, though? Since we closed port 8080 as part of the setup, I can’t get to tomcat anymore. For example, going to:

/manager/html

gives me a 403 page:

“By default the Host Manager is only accessible from a browser running on the same machine as Tomcat. If you wish to modify this restriction, you’ll need to edit the Host Manager’s context.xml file.”

I do have a user set up in there as directed (from the setting up tomcat 8 tutorial), but this doesn’t change anything. Restarted tomcat, still nothing.

How do you access the gui? Or is there a different way to deploy my web app war files?

Thanks