Unable to open Airflow UI post deployment - getting 503

I’ve pushed a Docker image to the repo via a CI actions using GitHub Actions. However despite a successful CI pipeline the Deployment doesn’t appear to work. When I go to open the Airflow UI I’m greeted with this:

I’ve pulled the same image from the repository and run it locally using astro dev start -i ... and it works just fine.

I’ve looked at the logs for the web server via the Astronomer and I can see the web server is being sent a SIGTERM (15) signal to gunicorn.