작업 완료 전에 요청 기한이 지난 경우입니다. 서버 작업은 이미 완료되었을 수도 있습니다.
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The deadline expired before the operation could complete. For operations that change the state of the system, this error may be returned even if the operation has completed successfully. For example, a successful response from a server could have been delayed long enough for the deadline to expire. HTTP Mapping: 504 Gateway Timeout
변경 내역: Extracted enum names, numeric aliases, and official source comments; comment syntax removed; original Korean contexts added. Successful OK is labeled status, not error.