This is not a mistake! Problem recently! It’s not completely permanent, but periodically a site that runs through CloudFlare stops responding and shows a 504 error, an error seen through Google WebMaster Console graph shows an increase of 500 errors since 10/06/19 and so far, I have a mirror of this very site that doesn’t use CloudFlare is fine there. What is the problem ?
Hi & welcome, here’s a link to all the tips for 5xx errors,
I’d start to troubleshoot there and after checking with your host logs let us know how you’re progressing.