Fixing "Uncaught ReferenceError: define is not defined" in Ghost Admin

Today, I encountered a frustrating issue: I couldn’t access the admin panel (dashboard) of my Ghost blog. The page was stuck on a blank white screen with no content loading. 😓

Curious, I opened the Firefox browser console to investigate. There, I found this JavaScript error:

Uncaught ReferenceError: define is not defined

After some digging, I discovered it was related to my NGINX cache setup. Here's how I fixed it.

My Environment

• OS: Ubuntu 20.04
• Ghost: Version 5 (running inside Docker)
• Web Server: NGINX 1.22 as a reverse proxy

The Fix: Adjust NGINX Cache Directory Permissions

The issue stemmed from improper ownership of the NGINX cache directory. Ghost’s admin panel was trying to serve cached JavaScript files, but NGINX didn’t have the right permissions to read/write them properly.

Step 1: Check the Ownership of /var/cache/nginx

Run:

ls -lah /var/cache/

Example output:

drwxr-xr-x  7 root root 4.0K Jun 19 17:11 nginx

As you can see, the nginx directory was owned by root. That’s the problem.

Step 2: Identify NGINX's User

Open your NGINX config file:

cat /etc/nginx/nginx.conf

Look for a line like:

user www-data;

In my case, NGINX runs as www-data.

Step 3: Fix the Ownership

Change the ownership of the cache directory so NGINX can properly access it:

sudo chown -R www-data:www-data /var/cache/nginx

Done! 🎉

After updating the ownership, I restarted NGINX and refreshed the Ghost admin page. Everything loaded perfectly—no more blank screen or console errors.

If you're running Ghost inside Docker with NGINX as a reverse proxy and hit this error, this fix might save you a lot of time.