I was trying to navigate to some pages on kernelnewbies.org and I got 502 bad gateway errors. The homepage works sporadically, but others throw the error mentioned. Examples include:

https://kernelnewbies.org/OutreachyIntro
https://kernelnewbies.org/FAQ
https://kernelnewbies.org/Documents
https://kernelnewbies.org/KernelJanitors
https://kernelnewbies.org/KernelProjects

I apologize if this information is redundant: I just subscribed to the list.