… and the 504 is back, Chrome as well as on Safari. With rare exceptions, it is just back. (edit*: gone!)
It doesn’t happen if a post is updated. Perhaps that helps to pinpoint the problem.
PMs are affected as well. (edit*: haven’t tested so far.)
P.S.: Monday Sept 16th: now I get an http 500 error message. No PMs. No email subscription. (edit*: gone!)
Edit*: Thanks a lot! I get Notifications! YEAH! *Sept 18 /edit …and it doesn’t work constantly anymore, Sept 21st.
Edit #2 October, all is fine, thanks a lot! /edit