How to fix ERR_BLOCKED_BY_ORB (network)

This error occurs when a browser security mechanism prevents the GTM script from loading. The browser expects JavaScript (Content-Type: application/javascript), but the server returns non-script content (such as an HTML error page or empty placeholder), so Chrome blocks the response.

With server-side GTM, this is usually caused by:

1. Ad blockers & privacy tools. DNS-level blockers intercept the standard /gtm.js request and return an empty or HTML response, which the browser then blocks as invalid script content.

2. The tagging server returning a non-script response. The server responds with an HTML page instead of JavaScript.

Solution:

1. Set up a Custom Loader by Stape. Instead of the standard /gtm.js path, the script loads through your own subdomain with a randomized path. Ad blockers no longer recognize it as a tracking script, and the ORB error is resolved.

2. Check what your tagging URL actually returns. Open the container script URL directly in the browser; if you see an HTML page or an error instead of JavaScript, check that your CDN manager isn't challenging the request.