>>/10584/
Had something similar happen. Archive today was stuck in CAPTCHA even if I filled it in. Researched it a bit (but it has been awhile)and the explanation was that the browser's cached page would reload either and error or CAPTCHA version of the website. Now, I had this happen on two web browsers,
Firefox and Librewolf (Firefox but striped of the bad anti-privacy things), Librewolf cleared when I closed it and restarted again (because Librewolf deletes everything unless otherwise asked too) but Firefox, I went through and cleared my cache and deleted cookies and for some reason it still didn't work. I tried a couple of other things, don't remember, but since I mainly used archive today on Librewolf over Firefox I just gave up on the problem, in like a month, it resolved itself. 
> Deleted a cookie of archive.ph's at brave://settings/content/all = did nothing. How do I fix this? I can use archive.ph in other computers on the same LAN without seeing any nginx-not-configured page.
I am not even sure that is your problem, but the TD;DR of that ramble is that, try clearing your cached pages too, if that is an option for whatever web browser you are using. 

I do think mine, and your problem, likely have/had something to do with cached pages; the browser getting stuck caching on a error page during one of the sites many down times.

 >>/10583/
> Hello Unicorn
This kind of thing does have my interest. Why? I wonder how many of these things have some connection/inspiration from MLP and FiM in particular. This is one of those things that is hard to judge as I could easily see someone random thinking and coming up with: "What is something else girly and cute that we can make like Hello Kitty? Unicorns! Of course!" and that be that. Yet, a lot of these, especially in more "nerdy" generes often do have a connection to FiM and horse show. This particular example looks a bit FiM like. My eyes can't quite discern the shade but at first I thought it was Dolores/Glimglam drawn as a Hello Kitty reference before I read your post.