I noticed the 'Run the Tests" button does not work for me at least on this lesson:
Request to access cookie or storage on “https://firstname.lastname@example.org/umd/react-dom.production.min.js” was blocked because we are blocking all third-party storage access requests and content blocking is enabled. create-a-complex-jsx-element
When I added freecodecamp.org to my third-party cookies whitelist, I then received this error:
Loading failed for the with source “https://www.googletagmanager.com/gtag/js?id=AW-795617839”. create-a-complex-jsx-element:342:1
onmozfullscreenchange is deprecated. index.js:52:37
onmozfullscreenerror is deprecated. index.js:52:37
Unhandled promise rejection TypeError: “t[e] is undefined”
My DNS blocks googleanalytics but it appears that will crash the test function. Not sure if this is a personal problem or if it applies to other users.