Why does hosting external resources on a subdomain not resolve the "Access-Control-Allow-Origin missing" error in Webflow? Is it because the Webflow site is not hosted on the same server as the subdomain and is only pointed to with an A record? Is there another solution or a way to set header policies in Webflow to address this issue?

When hosting external resources on a subdomain in Webflow, it does not automatically resolve the "Access-Control-Allow-Origin missing" error because of how the browser enforces a security mechanism called "Same Origin Policy."

The Same Origin Policy is a security measure implemented by browsers to prevent cross-origin resource sharing, which could potentially be a security risk. Under this policy, web browsers enforce that a web page can only interact with resources (i.e., scripts, stylesheets, fonts, images) on the same domain, port, and protocol from which it was originally served. Any interaction attempted with resources from a different origin, as indicated by the URL, triggers a "Access-Control-Allow-Origin missing" error.

Hosting external resources on a subdomain does not resolve this error in Webflow because the subdomain is considered a different origin or domain. While it is possible to point the subdomain to the same server as the main domain using A records, the browser still recognizes them as distinct origins because of the URL.

To resolve the "Access-Control-Allow-Origin missing" error, you need to adjust the server's response headers to include the appropriate Access-Control-Allow-Origin header. This header tells the browser which domains are allowed to access the resources. However, in Webflow, you do not have direct access to the server configuration or the ability to modify server headers, as it is a managed hosting platform.

Luckily, there is a solution to this issue. Instead of hosting the external resources on a subdomain, you can host them on the same domain as your Webflow site. By doing this, the browser will recognize the resources as originating from the same domain and thus avoid triggering the error.

To host the resources on the same domain, you can either upload them directly to Webflow if they are supported file types, or you can use a third-party file hosting service that supports cross-origin sharing. These services handle the necessary headers and provide you with URLs that can be used in Webflow without triggering the "Access-Control-Allow-Origin missing" error.

In summary, hosting external resources on a subdomain in Webflow does not resolve the "Access-Control-Allow-Origin missing" error due to the Same Origin Policy enforced by browsers. The best solution is to host the resources on the same domain as your Webflow site or use a third-party file hosting service that supports cross-origin sharing.