Fix Issue Outlook is Unable to Connect to the Proxy Server Error Code 0

Isha Ratra | July 17th, 2018 | Errors

Nowadays, the most frequently used email program is Microsoft Outlook. But, it is not always easy to work with Outlook application. At certain times, users face various issues while working, which primarily lead to the occurrence of errors. Out of them, one such error message is Outlook is Unable to Connect to the Proxy Server error code 0. Therefore, in this blog, we are going to discuss manual approaches using which a user can easily fix this error in a hassle free way. Before that, let us understand all the possible reasons behind this type of error.

Overview of Generating Error Messages

Many times, when MS Outlook is connected to the server via RPC (Remote Procedure Call) connection or HTTP connection, the following messages may be generated:

  • There is an issue with proxy server’s security certificate due to which this error Outlook is not able to connect to the proxy server error code 0 gets generated.
  • Sometimes, the name on the security certificate is invalid or does not matches the name of a website. This leads to the generation of this error.

  • A problem that comes with a proxy server’s security certificate. This security certificate is not from a trusted certifying authority. Therefore, the following error message appears Outlook is unable to connect to the proxy server error code 0.

Most Common Reasons Behind this Error

There are so many reasons associated with an occurrence of the above-described errors. These errors may occur in case any of the following conditions exist:

  1. The certification authority is not trusted at the root.
  2. Certification Authority (CA) is essential for getting connected to a server.
  3. There are more chances that the certificates have been revoked or stand invalid.
  4. The certificate does not match the name of the website to which the connection is made.
  5. A third-party browser or add-ins are preventing the access to a particular site.

Resolution to Fix Outlook is Not Able to Connect to the Proxy Server Error Code 0

Go through the following methods by which users can overcome this error. Let us have a look:

1. Check & Analyze the Certificate
In any case, users may encounter either Error 1 or 2, it is recommended to analyze the certificate thoroughly. There are two things needed to be verified in the certificate. Initially, a certificate could not be expired and secondly, the information stated in the Subject field will match with a site name. Follow the below-described steps to analyze the certificate:

  • Under the Address Bar of the Internet Explorer, enter this site https://www.[server_name].com/RPC. Then, click Enter and connect to the RPC server
  • In the lower corner of a web browser, double click and choose the padlock icon
  • After that, you can select an option Details
  • Under the dialog box, check the Certificate validation date and Subject as well. In any case, a certificate has been expired, contact your system administrator. In case, the subject field does not match, then changes are made as required

2. Installation of a Trusted Root Certificate
You can follow the below-stated approach in case you may receive Error 3:

  • Under the Certificate dialog box, choose the Install Certificate
  • Now, place all certificates in the following store is checked
  • Select Browse option
  • Choose the Trusted Root Certification Authority option and press OK button
  • Press Next and then, Finish completing the process.

3. Disable Third-Party Browser and Add-in
All these errors can also be removed, by disabling a third party browser and add-in. Let us have a look:

  • Select the Start icon and then, choose Run
  • In the dialog box, type exe/safe and click Ok button. This can start MS Outlook in safe mode
  • In any case, Outlook starts in the Safe mode, then undoubtedly the issue is caused by third-party add-ons and the only way is to disable them.

To disable the third-party add-ons, follow the below-stated steps:

  • Open Microsoft Outlook and select File tab
  • Click on Options and select the Add-ins option from the left-side menu
  • Under the Add-ins segment, select and remove add-ins that you want to disable
  • Close and then, restart MS Outlook

Final Thoughts

Outlook is the desktop-based email client, but at times, while working over it is quite challenging. In this blog, we have discussed three different methods by which users can fix outlook is unable to connect to the proxy server error code 0 in an absolute way. Further, we have explained all the possible reasons behind the occurrence of this error.