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:
Hello Community, Jessica here from the Confluence product marketing team! Today I wanted to get your takes on project planning –– what works, what doesn’t, how do you know if you’re doing it r...
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