The error 502 means The server is currently unavailable (because it is overloaded or down for maintenance). Generally, this is a temporary state.
I recommend you to check your Confluence connections. Looks like your proxy is trying to communicate to Confluence, but Confluence is too busy to reply.
These links can be useful:
Hi team, I’m Avinoam, a product manager on Confluence Cloud, and today I’m really excited to let the Community know that all customers can now try out the new editing experience and see some of the ...
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