503 Service Unavailable错误在所有操作系统和 Web 浏览器中都很常见。它甚至可以出现在手机和基于控制台的网络浏览器中。浏览网页或使用基于 Web 的应用程序时发生错误，并且网站的服务器当时无法加载内容。
尝试这些简单的解决方案来修复此错误消息。
如何修复 503 服务不可用错误代码(How to Fix 503 Service Unavailable Error Code)
当您看到 503 Service Unavailable之类的状态代码时，您的第一反应可能是质疑您做错了什么——但请记住，此消息仅在响应服务器端错误时出现。虽然您的选择通常有限，但您仍然可以做一些事情。
刷新页面(Refresh the Page)
错误 503 Service Unavailable 消息通常表示临时问题。有时，清除错误代码只需按F5或CTRL + R即可刷新网页。重新加载网站，看看您是否获得访问权限。但是，它也可能使问题恶化，尤其是在被意外涌入的用户淹没的页面上。
注意：(Note:)如果您在结帐过程的最后一步收到此错误，反复刷新页面可能会导致多次交易和信用卡扣款。
重新启动调制解调器和路由器(Restart Your Modem and Router)
在大多数情况下，Web 服务器对错误负责。但是，如果您看到 503 Service Temporarily Unavailable，则问题可能出在路由器内的DNS 服务器配置中。(DNS server configuration)错误(Bad)的代码或故障可能会导致网站拒绝加载。
重新启动调制解调器和路由器，一旦它们重新启动，请重试网站或程序。重新启动这两个设备会“刷新”您的临时代码缓存，这通常是问题的原因。
过一会再来检查(Check Back Later)
有时您最好的选择是等待，尤其是当网站受到DDOS 攻击时(DDOS attack)。这是分布式拒绝服务的缩写，意味着网站流量超载。在大多数情况下，DDOS攻击是恶意的，但有时小型网站可能会收到比平时更多的流量（例如，如果它访问Reddit的首页）并因此遭受临时中断。
如果网站因流量耗尽其可用带宽而关闭，刷新页面只会让问题变得更糟。给它十分钟，然后再试一次。如果您不确定网站是否因流量而关闭，请考虑使用类似Is It Down Right Now 之类的网站？(Is It Down Right Now?)
联系网站(Contact the Website)
如果您的故障排除尝试均无效，请联系网站或托管服务提供商。问题可能出在WordPress内部，或者是由于需要所有者干预 的错误插件所致。(faulty plugin)
如果您不确定该联系谁，请访问https://lookup.icann.org/。
- (Enter)在搜索栏中输入URL或域名，然后选择查找。(Lookup.)
- 下一页将显示名称、注册 ID、域状态、名称服务器等。如果可用，您可以向下滚动页面并查看所有者、他们的联系信息等。在许多情况下，出于隐私目的，这些信息会被删除。
如何在您的网站上修复 HTTP 错误 503(How to Fix HTTP Error 503 On Your Website)
由于HTTP错误 503 通常是服务器错误，因此您有责任在您的网站上修复它。您可能会看到您网站的流量下降，因为没有人可以访问它。
尝试这些修复之一。
重启你的服务器(Restart Your Server)
就像重新启动路由器以最终用户身份工作一样，重新启动服务器可以为观众恢复对您网站的访问。您可以通过访问您的虚拟主机管理页面来重新启动服务器。服务器重新启动通常需要几分钟时间。
寻找自动维护(Look For Automatic Maintenance)
如果您通过第三方进行网络托管（大多数人都这样做），自动维护有时会导致 503 错误。这种维护往往只持续几分钟，但可能导致您的页面出现故障。请留意维护计划，以了解您的网站何时可能无法访问。
当WordPress进行更新时，它会引发HTTP 503错误。
检查您的防火墙配置设置(Check Your Firewall Configuration Settings)
如果您没有正确配置服务器的防火墙，它可能会将一系列相关的 IP 地址误解为DDOS攻击。同样(Again)，确切地确定如何配置您的防火墙取决于各种因素，包括您的管理系统和服务提供商，因此这里不可能提供一个明确的逐步过程。
如果您怀疑您的防火墙是罪魁祸首，请查看您的服务器端日志。如果您无法识别那里的信息，请联系您的托管服务提供商的客户服务寻求帮助。待命的客户服务团队可以帮助调试您的站点，并确定故障防火墙是否导致问题或其他原因。
网站(Website)错误代码根据其第一位数字具有不同的含义。例如，任何以 5 开头的代码都表示服务器端错误，而任何以 4 开头的代码（如臭名昭著的403 禁止错误(403 forbidden error)）表示客户端错误。虽然修复服务器错误的方法并不总是很多，但了解您的选择仍然是件好事。
What Is a 503 Service Unavailable Error (and How to Fix It)
The 503 Service Unavaіlable error is common acrоss all operating systems and web browsers. It can еven appear on mоbile phones and іn console-based web browsers. The error occurs while browsing the web or when using a web-based applicаtion and the website’s server isn’t аble to load the content at the time.
Try these simple solutions to fix this error message.
How to Fix 503 Service Unavailable Error Code
When you see a status code like 503 Service Unavailable, your first instinct may be to question what you did wrong – but remember that this message only appears in response to a server-side error. While your options are usually limited, you can still do a few things.
Refresh the Page
The error 503 Service Unavailable message typically indicates a temporary problem. Sometimes all it takes to clear the error code is to press F5 or CTRL + R to refresh the web page. Reload the site and see if you gain access. However, it might also worsen the problem, especially on pages swamped by an unexpected influx of users.
Note: If you receive this error at the last step of the checkout process, repeatedly refreshing the page could result in multiple transactions and charges to your credit card.
Restart Your Modem and Router
In most cases, the web server is responsible for the error. However, if you see 503 Service Temporarily Unavailable, the problem might lie within the DNS server configuration within your router. Bad code or a glitch may result in the website refusing to load.
Restart your modem and router and once they have come back on, retry the website or program. Restarting these two devices “flushes” your cache of temporary code, which is often the cause of the problem.
Check Back Later
Sometimes your best option is to wait it out, particularly if a website comes under DDOS attack. That’s short for distributed denial of service and means the website is overloaded by traffic. In most cases, DDOS attacks are malicious, but sometimes a small website may receive more traffic than usual (like if it hits the front page of Reddit) and suffer a temporary outage as a result.
If the site is down because traffic has nuked its available bandwidth, refreshing the page is just going to make the problem worse. Give it ten minutes and try again. If you aren’t sure the website is down due to traffic, consider using a website like Is It Down Right Now?
Contact the Website
Contact the website or hosting provider if none of your troubleshooting attempts worked. The problem might lie within WordPress or be due to a faulty plugin requiring the owner’s intervention.
If you aren’t sure who to contact, go to https://lookup.icann.org/.
- Enter the URL or domain name into the search bar and select Lookup.
- The next page will display the name, registry ID, domain status, nameservers, etc. If available, you can scroll down the page and view the owner, their contact information, etc. In many cases, this information is removed for privacy purposes.
How to Fix HTTP Error 503 On Your Website
Since the HTTP error 503 is typically a server error, you are responsible for fixing it on your website. You might see a drop in traffic to your website since no one can access it.
Try one of these fixes.
Restart Your Server
Just as restarting the router works as an end-user, restarting your server can restore access to your website for viewers. You can reboot the server by accessing your web hosting management page. It usually takes several minutes for a server to restart.
Look For Automatic Maintenance
If you go through a third party for web hosting (as most people do), automatic maintenance can sometimes cause 503 errors. This maintenance tends to last only for a few minutes but can result in your page going down. Keep an eye out for maintenance schedules to know when your website might be unreachable.
When WordPress undergoes updates, it throws an HTTP 503 error.
Check Your Firewall Configuration Settings
If you haven’t configured your server’s firewall correctly, it can misinterpret a series of related IP addresses as a DDOS attack. Again, determining exactly how to configure your firewall relies on various factors, including your management systems and service provider, so it’s impossible to provide a definitive step-by-step process here.
If you suspect your firewall is to blame, look to your server-side logs. If you can’t discern the information there, reach out to your hosting provider’s customer service for help. The on-call customer service teams can help debug your site and determine whether a faulty firewall is causing the problem or it’s something more.
Website error codes have different meanings depending on their first digit. For example, any code that begins with a 5 indicates a server-side error, while any code that starts with 4 (like the infamous 403 forbidden error) indicates a client-side error. While there isn’t always a lot you can do to fix a server error, it’s still good to know your options.
