如果您在浏览互联网时遇到错误 503 Backend Fetch Failed Varnish 缓存服务器,本指南可以提供帮助!
我们将讨论常见原因,并为您提供经过 WR 专家测试的方法来立即解决问题。
什么是后端错误503?
503 Backend Fetch Failed Varnish 缓存服务器表示您尝试访问的网站或 Web 服务当前不可用,或者您的互联网连接不稳定。其他可能的原因有:
- 服务器正在维护中。
- 网站被认为是可疑的,因此被您计算机上的 Adblocker 阻止。
- 网站服务器没有足够的内存来处理传入的信息。
如何修复错误 503 后端获取失败?
在继续执行任何步骤来修复 503 后端获取失败错误消息之前,请执行以下初步检查:
- 使用其他浏览器可以直接解决此问题以及其他问题,例如503 第一个字节超时。
- 按F5刷新网页。
- 关闭所有其他活动选项卡或重新启动计算机。
1. 重新启动路由器(适用于前端和后端用户)
- 从电源插座上拔下调制解调器和路由器的插头。
- 等待 15-30 秒,然后将调制解调器重新插入电源插座。
- 再次等待 1 或 2 分钟,然后打开路由器,
- 路由器将启动;等待所有指示灯变绿,然后测试您的连接。
重新启动路由器可以帮助清除本地网络问题并刷新 DNS 信息。如果网站的问题出在您这边,那么问题就可以解决。这也有助于解决类似的网站相关问题,例如 503 错误不可用。
2. Ping 路由器以检查连接
- 按 Windows 键,输入 cmd 并单击以管理员身份运行。
- 输入以下命令对 Google DNS 服务器执行 ping 操作并显示是否有任何数据包丢失,然后点击Enter:
ping 8.8.8.8
对路由器执行 Ping 操作可以帮助诊断本地网络连接问题并排除网络中可能出现的问题。
3.清除浏览器缓存
- 打开您喜欢的浏览器。在这里,我们使用 Google Chrome 演示这些步骤。
- 转至三点图标,然后点击设置。
- 点击隐私和隐私安全选项,然后点击清除浏览数据。
- 对于时间范围,从下拉列表中选择所有时间,然后勾选 Cookie 和其他网站数据旁边的复选标记,& 缓存的图像和文件。
- 单击清除数据。
如果您由于浏览器中存储的缓存数据损坏或过时而无法访问该网站,这些步骤可以帮助您将其删除。
清除缓存可以帮助您解决错误 503 证书已过期问题,这样您就不会被限制访问任何网站。< /span>
4. Reset your browser
- Open your preferred browser. Here, we are demonstrating the steps using Google Chrome.
- Go to the three dots icon, then click Settings.
- From the left side, select Reset Settings.
- Click Reset settings to their original defaults.
- Now, on the following prompt, select Reset settings.
If you can use the website on another browser but can’t open it on the preferred browser, it is time to reset it to default settings.
5. Re-enable the Varnish plugin (Backend users)
- Go to your website Control Panel and log in using the credentials.
- Next, go to Web Accelerator, then click Manage Varnish.
- Click Disable Varnish.
- Next, click Confirm Action to disable.
- Now click Enable Varnish.
If the Error 503 Backend Fetch Failed issue is at the server end and caused by Varnish cache misconfiguration or other issues, refreshing the plugin can help. However, if the plugin is already disabled, try enabling it and check if the issue is resolved.
6. Modify the Varnish & NGIX configuration files (Backend users)
- Ensure you have logged in using admin privileges. Locate & open the file in Ubuntu from this path in the text editor of your choice: /etc/varnish/default.vcl
- Search this line and remove /pub from it:
-
.probe = {.url = "/pub/health_check.php";
-
- After the change, it should look like this:
-
.probe = {.url = "/health_check.php";
-
- If you don’t see /pub in the line, try adding it. Save the file.
Now locate nginx.conf.sample file in the Magneto 2 root folder, follow these steps:
- Locate this line and add health_check:
-
location ~ (index|get|static|report|404|503)\.php$ {
-
- After the change, it should look like this:
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location ~ (index|get|static|report|404|503|health_check)\.php$ {
-
- Press Ctrl + S to save the changes.
7. Edit the cache length (Backend users)
- Go to the Varnish configuration file:
etc/default/varnish
- Look for the http_resp_hdr_len line and change its value to 70000 bytes. In case if the parameter doesn’t exist, look for thread_pool_max and add this line:
-p http_resp_hdr_len=70000 \
- Locate http_resp_size and change its value to 100000; it should look like this:
-p http_resp_size=100000 \
- Press Ctrl + S to save the changes.
In case nothing worked for you, then try considering the website admin, explain the issue and fixes you tried for further assistance.
If you have any questions or suggestions about the subject, feel free to mention them in the comments section below.
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