That`s a pain in the butt! I checked my link & it works for me. It must be a sporadic problem?
I used the Trial Teams tab at the top of the page, then scrolled to find the Boost Lab Vitamin C TT. You might want to try that. The URL is different, but for me, it opens the same article.
https://cloudfront.beautyheaven.com.au/trial/boost-lab-vitamin-c-brightening-serum
[EDIT] Hang on, something`s dodgy. Both links open the article for me, but the pages open with me logged out. When I try to log in, I get an error page. I had this with a random article a few weeks ago. After a couple of weeks of trying, it suddenly opened one day.
Bh glitch, Sally!