503 Service Unavailable - HTTP - MDN Web Docs

超文本傳輸協定(英文：HyperText Transfer Protocol (HTTP) ) 503 Service Unavailable 表示目前伺服器暫時不能處理連線的請求。

SkiptomaincontentSkiptosearchSkiptoselectlanguage給開發者的網頁技術文件HTTPHTTP狀態碼503ServiceUnavailableArticleActions正體中文(繁體)ThispagewastranslatedfromEnglishbythecommunity.LearnmoreandjointheMDNWebDocscommunity.狀態規範瀏覽器相容性請參閱了解更多RelatedTopics HTTP Guides: ResourcesandURIs IdentifyingresourcesontheWeb DataURIs IntroductiontoMIMEtypes CommonMIMEtypes Choosingbetweenwwwandnon-wwwURLs HTTPguide BasicsofHTTP OverviewofHTTP EvolutionofHTTP HTTPMessages AtypicalHTTPsession ConnectionmanagementinHTTP/1.x Protocolupgrademechanism HTTPsecurity ContentSecurityPolicy(CSP) HTTPPublicKeyPinning(HPKP) HTTPStrictTransportSecurity(HSTS) Cookiesecurity X-Content-Type-Options X-Frame-Options X-XSS-Protection Mozillawebsecurityguidelines MozillaObservatory HTTPaccesscontrol(CORS) HTTPauthentication HTTPcaching HTTPcompression HTTPconditionalrequests HTTPcontentnegotiation HTTPcookies HTTPrangerequests HTTPredirects HTTPspecifications Featurepolicy References: HTTPheaders AcceptAccept-CH Experimental Non-Standard Deprecated Accept-CH-LifetimeAccept-CharsetAccept-EncodingAccept-LanguageAccept-PatchAccept-PostAccept-RangesAccess-Control-Allow-CredentialsAccess-Control-Allow-HeadersAccess-Control-Allow-MethodsAccess-Control-Allow-OriginAccess-Control-Expose-HeadersAccess-Control-Max-AgeAccess-Control-Request-HeadersAccess-Control-Request-MethodAgeAllowAlt-SvcAuthorizationCache-ControlClear-Site-DataConnectionContent-Disposition Experimental Non-Standard Deprecated Content-DPRContent-EncodingContent-LanguageContent-LengthContent-LocationContent-RangeContent-Security-PolicyContent-Security-Policy-Report-OnlyContent-TypeCookieCross-Origin-Embedder-PolicyCross-Origin-Opener-PolicyCross-Origin-Resource-PolicyDate Experimental Device-MemoryDigestDNT Experimental Downlink Experimental Non-Standard Deprecated DPR Experimental Early-Data Experimental ECTETagExpectExpect-CTExpires Experimental Feature-PolicyForwardedFromHostIf-MatchIf-Modified-SinceIf-None-MatchIf-RangeIf-Unmodified-SinceKeep-Alive Non-Standard Deprecated Large-AllocationLast-ModifiedLinkLocationNELOrigin Deprecated PragmaProxy-AuthenticateProxy-Authorization Deprecated Public-Key-Pins Deprecated Public-Key-Pins-Report-OnlyRangeRefererReferrer-PolicyRetry-After Experimental RTTSave-Data Experimental Sec-CH-UA Experimental Sec-CH-UA-Arch Experimental Sec-CH-UA-Bitness Experimental Sec-CH-UA-Full-Version Experimental Sec-CH-UA-Full-Version-List Experimental Sec-CH-UA-Mobile Experimental Sec-CH-UA-Model Experimental Sec-CH-UA-Platform Experimental Sec-CH-UA-Platform-VersionSec-Fetch-DestSec-Fetch-ModeSec-Fetch-SiteSec-Fetch-UserSec-WebSocket-AcceptServerServer-TimingService-Worker-Navigation-PreloadSet-CookieSourceMapStrict-Transport-SecurityTETiming-Allow-OriginTkTrailerTransfer-EncodingUpgradeUpgrade-Insecure-RequestsUser-AgentVaryVia Experimental Non-Standard Deprecated Viewport-WidthWant-Digest Deprecated Warning Experimental Deprecated WidthWWW-AuthenticateX-Content-Type-OptionsX-DNS-Prefetch-Control Non-Standard X-Forwarded-For Non-Standard X-Forwarded-Host Non-Standard X-Forwarded-ProtoX-Frame-OptionsX-XSS-Protection HTTPrequestmethods CONNECTDELETEGETHEADOPTIONSPATCHPOSTPUTTRACE HTTPresponsestatuscodes 100Continue101SwitchingProtocols103EarlyHints200OK201Created202Accepted203Non-AuthoritativeInformation204NoContent205ResetContent206PartialContent300MultipleChoices301MovedPermanently302Found303SeeOther304NotModified307TemporaryRedirect308PermanentRedirect400BadRequest401Unauthorized402PaymentRequired403Forbidden404NotFound405MethodNotAllowed406NotAcceptable407ProxyAuthenticationRequired408RequestTimeout409Conflict410Gone411LengthRequired412PreconditionFailed413PayloadTooLarge414URITooLong415UnsupportedMediaType416RangeNotSatisfiable417ExpectationFailed418I'mateapot422UnprocessableEntity425TooEarly426UpgradeRequired428PreconditionRequired429TooManyRequests431RequestHeaderFieldsTooLarge451UnavailableForLegalReasons500InternalServerError501NotImplemented502BadGateway503ServiceUnavailable504GatewayTimeout505HTTPVersionNotSupported506VariantAlsoNegotiates507InsufficientStorage508LoopDetected510NotExtended511NetworkAuthenticationRequired CSPdirectives CSP:base-uriCSP:block-all-mixed-contentCSP:child-srcCSP:connect-srcCSP:default-srcCSP:font-srcCSP:form-actionCSP:frame-ancestorsCSP:frame-srcCSP:img-srcCSP:manifest-srcCSP:media-srcCSP:navigate-toCSP:object-srcCSP:plugin-typesCSP:prefetch-src Deprecated CSP:referrerCSP:report-toCSP:report-uriCSP:require-sri-forCSP:require-trusted-types-forCSP:sandboxCSP:script-srcCSP:script-src-attrCSP:script-src-elemCSPsourcevaluesCSP:style-srcCSP:style-src-attrCSP:style-src-elemCSP:trusted-typesCSP:upgrade-insecure-requestsCSP:worker-src CORSerrors Reason:CORSheader'Access-Control-Allow-Origin'doesnotmatch'xyz'Reason:CORSrequestdidnotsucceedReason:CORSdisabledReason:CORSrequestexternalredirectnotallowedReason:invalidtoken'xyz'inCORSheader'Access-Control-Allow-Headers'Reason:invalidtoken'xyz'inCORSheader'Access-Control-Allow-Methods'Reason:DidnotfindmethodinCORSheader'Access-Control-Allow-Methods'Reason:expected'true'inCORSheader'Access-Control-Allow-Credentials'Reason:missingtoken'xyz'inCORSheader'Access-Control-Allow-Headers'fromCORSpreflightchannelReason:CORSheader'Access-Control-Allow-Origin'missingReason:MultipleCORSheader'Access-Control-Allow-Origin'notallowedReason:CredentialisnotsupportediftheCORSheader'Access-Control-Allow-Origin'is'*'Reason:CORSheader'Origin'cannotbeaddedReason:CORSpreflightchanneldidnotsucceedReason:CORSrequestnotHTTP Feature-Policydirectives Experimental Feature-Policy:accelerometer Experimental Feature-Policy:ambient-light-sensor Experimental Feature-Policy:autoplay Experimental Feature-Policy:battery Experimental Feature-Policy:camera Experimental Feature-Policy:display-capture Experimental Feature-Policy:document-domain Experimental Feature-Policy:encrypted-media Experimental Feature-Policy:fullscreen Experimental Feature-Policy:gamepad Experimental Feature-Policy:geolocation Experimental Feature-Policy:gyroscope Experimental Non-Standard Feature-Policy:layout-animations Experimental Non-Standard Feature-Policy:legacy-image-formats Experimental Feature-Policy:magnetometer Experimental Feature-Policy:microphone Experimental Feature-Policy:midi Experimental Non-Standard Feature-Policy:oversized-images Experimental Feature-Policy:payment Experimental Feature-Policy:picture-in-picture Experimental Feature-Policy:publickey-credentials-get Experimental Feature-Policy:screen-wake-lock Experimental Feature-Policy:speaker-selection Experimental Feature-Policy:sync-xhr Experimental Non-Standard Feature-Policy:unoptimized-images Experimental Non-Standard Feature-Policy:unsized-media Experimental Feature-Policy:usb Experimental Feature-Policy:web-share Experimental Feature-Policy:xr-spatial-tracking 狀態規範瀏覽器相容性請參閱了解更多503ServiceUnavailable 超文本傳輸協定(英文：HyperTextTransferProtocol(HTTP))503ServiceUnavailable表示目前伺服器暫時不能處理連線的請求。

起因通常是伺服器正在進行維護或是當下流量過載。

這種錯誤回傳應該是暫時性的，並且Retry-After(en-US)HTTPheader中要盡可能描述到系統大概恢復正常的時間。

. 注意：回傳這種錯誤的同時，也要同時顯示一張對使用者友善的網頁，來簡單描述問題。

回傳此錯誤時，務必注意和快取存取相關的標頭（Caching-relatedheaders），因為503狀態通常要是暫時性的，而這種回應不應該被暫存至快取。

狀態503ServiceUnavailable規範SpecificationHypertextTransferProtocol(HTTP/1.1):SemanticsandContent#status.503瀏覽器相容性BCDtablesonlyloadinthebrowser以下資訊是從MDN的GitHub取得(https://github.com/mdn/browser-compat-data). 請參閱 Retry-After(en-US) 了解更多一般知識 HTTP/1.1:StatusCodeDefinitions HTTPError503 503ServiceUnvailaibleWordPress 如何修復在WordPress當中「503ServiceUnavailableError」的問題？ Foundaproblemwiththispage?EditonGitHubSourceonGitHubReportaproblemwiththiscontentonGitHubWanttofixtheproblemyourself?SeeourContributionguide.Lastmodified:2022年6月1日,byMDNcontributors