I host a rails app on a Digital Ocean droplet. The app lives under app.mysite

I wanted to set up a staging server, so I set up a new droplet using a snapshot of the original. I've set up a record for the new subdomain and updated the NGINX config to point to staging.mysite and all seemed ok.

However, I get a Blocked host: error when I access the staging site. So I check the environment being used. It was using Development by default. So I update the development.rb environment file to include the following:

config.hosts << "staging.mysite"

I still get the error. I've tried restart rails, the server everything but no joy. This is my 3rd evening trying to get this setup and I'm out of ideas. I've been using ChatGPT to help me troubleshoot but nothing has changed the outcome.

If anyone has any suggestions for things I should try I would be forever grateful. This is driving me crazy.