502 Bad Gateway
A proxy or gateway received an invalid response from the server behind it. It often appears during deployments or crashes.
503 Service Unavailable
The server is temporarily unable to handle requests, often due to maintenance or overload.
504 Gateway Timeout
The gateway waited too long for the server to respond.
What to do
Wait and retry later. Errors do not mean an address has changed, and they are not a reason to try unverified Mars Market alternatives.