diff --git a/docs/production/install-existing-server.md b/docs/production/install-existing-server.md
index a2418ac606..2fd88ef420 100644
--- a/docs/production/install-existing-server.md
+++ b/docs/production/install-existing-server.md
@@ -52,6 +52,10 @@ Zulip's Puppet configuration will change the ownership of
 `/var/log/nginx` so that the `zulip` user can access it. Depending on
 your configuration, this may or may not cause problems.
 
+Depending on how you have configured `nginx` for your other services,
+you may need to add a `server_name` for the Zulip `server` block in
+the `nginx` configuration.
+
 ### Puppet
 
 If you have a Puppet server running on your server, you will get an