Fix Outlook Error Code 8 When Outlook is Unable to Connect to the Proxy Server 

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  • Published on
    December 27th, 2018
  • Updated on
    October 3, 2020
  • Read Time
    4 minutes
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Microsoft Outlook is a popular email client application used by millions of users all around the world. But sometimes things don’t go well while working with Outlook. Whenever anything goes wrong, you receive an error. There are numerous error messages which appear time to time if there’s any sort of problem in the Outlook client. In this article, we’re going to discuss the Outlook error code 8, troubleshoot it with some common reasons. behind it.

Outlook is unable to connect to the proxy server
Let’s suppose you open Microsoft Outlook on your system. But the Outlook client fails to open. Instead, you receive an error message saying, “Outlook is unable to connect to the proxy server”.

Outlook is unable to connect

When Outlook tries to connect to the server by using a remote procedure call (RPC) connection or a secure HTTP (HTTPS) connection, you may encounter the error message shown above. You must be wondering the reasons which are highly responsible for this Outlook error message. If you have no idea, let me help you with that.


Most Common Reasons

Below is the list of the highly responsible reasons behind the problem:

• If the connection to the server requires a certification authority, you may receive this error message.
• You haven’t trusted the certification authority at the root.
• The certificate may be invalid or revoked.
• The certificate doesn’t match the name of the site.

How to Troubleshoot Outlook error code 8?

There are some easy methods which you can use for troubleshooting the Outlook error code 8.

Method 1: Check the Certificate

Before you can try anything, you need to examine the certificate. Follow these simple steps to do that:

• First, launch Internet Explorer on the computer. Then connect to the RPC server or any other secure server by typing in the address bar. Hit Enter.
• You can see a padlock icon located in the lower-right corner of the browser. Double click it.
• Now click the Details tab. Here you need to check the information in these two fields:
Valid to: In this field, you’ll see the date till how long the certificate will be valid.
Subject: Make sure the entry in this field should match the site name.

Method 2: Install Trusted Root Certificate

If the above method fails or doesn’t work, you should try to fix the error code 8 in Outlook by installing the trusted root certificate. Follow these simple steps to do that:
• On the Certificate dialog box, click the Install Certificate. Then click the Next button to continue the process.
• Now click the Place all certificate in the following store check-box. Click the Browse button.
• Click the Trusted Root Certification Authorities, and then click OK. Now click the Next button to continue the process.
• Finally, click Finish and OK.

Method 3: Remove 3rd Party Add-ins

If you’ve tried both the above methods but still receiving the error code 8 in Outlook, maybe the error is associated with the 3rd party add-ins. So it’s better to start the Outlook client in safe mode. Click Start > Run and type outlook.exe/safe, and hit Enter. If the Outlook client starts in safe mode with no problem, the real culprit is any of the 3rd party add-ins you’re using. If there are too many add-ins, it’s always difficult to find the faulty one. So before you can delete any, you should try to disable them one by one. This process may take some time, but you’ll find the faulty add-in which you need to remove from the Outlook client.

Sometimes 3rd party browser add-ins can also cause this issue. So you should try to disable them also to check whether the issue is resolved or not. You can disable the 3rd party browser add-ins in the Internet Explorer.
You may also like to read: Solve Outlook error code 0x80072f06


It’s a bit frustrating to receive error messages while using our favorite email client, Microsoft Outlook. In this article, we’ve discussed one of the most common Outlook error messages, “Outlook is unable to connect to the proxy server (Outlook error code 8)”. The article has explained a few easy methods to troubleshoot this Outlook error.

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