Deploying Craft 3 site to production has working admin but 503 front end

Question

I have just deployed my first Craft 3 site to a production server with the following process:

1. Deploying git repo to the server
2. Then running the composer command to download the required files for Craft etc that were ignored from git (from https://nystudio107.com/blog/setting-up-a-craft-cms-3-project)
3. Set up database etc

However, when I open the site in the browser it is returning a 503 Service Unavailable error yet the admin side of the site works absolutely fine.

Answer 1

isSystemOn was set to false. IDIOT.