WebTex not rendering due to failed CORS

[xobust]

WebTex does not render for me on Canvas(kth.instructure.com).
There seems to be some missconfiguration with the origin policy, but it is specific to Firefox.

Browser: Firefox 66.0.2 (64-bit)
Example:

Firefox Console log:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://www.kth.se/api/webtex/v1/WebTex?D=1&tex=%5Cdisplaystyle+s. (Reason: CORS request did not succeed)

[Delodax]

@xobust : Hi! How are you using WebTex from Canvas?