已解决:Outlook 无法连接代理服务器错误

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Overview:

An Outlook user experiences many  Outlook errors. Few of them A problem so complex is related to the error The Outlook is unable to connect the proxy server ” from the Exchange server. This article provides a brief introduction to the Exchange proxy server and what causes the error. At the end of the reading, you will be able to understand and fix the error The Outlook is unable to connect the proxy server.

The error: Outlook unable to connect to the proxy server

We all know that Outlook is the most widely used email application as compared to other applications. Outlook is not only an email client but also provides many other additional features such as calendar, task manager, contact manager, notes, journal, etc. Despite its high profile, Outlook is prone to errors .

Quick navigation:

About the Exchange Proxy Server: Why can’t I connect?

Why does Outlook say it cannot connect to the proxy server?

How to fix proxy server security certificate in Outlook?

frequently asked questions

About Outlook Exchange Proxy Server: Why can’t I connect?

Exchange server:

Outlook Exchange Server uses the Mailbox server role (multi-role server) to send outbound emails through Send connectors. Send connectors allow you  to send email from your Exchange server to other domains on the Internet. When you click on the properties of Exchange’s Send connector, you’ll find an option to proxy through a Client Access server.

proxy server:

A proxy server is a network from which all your client queries or requests will be sent to the main server. Basically, a proxy server acts as an intermediary network to send and receive requests from clients to servers and vice versa. The error: Outlook cannot connect to the proxy server has something to do with the security certificate of the proxy server.

Security certificate:

Security certificates are used to authenticate MS Exchange servers to only communicate with authenticated servers. When Microsoft Outlook tries to connect to the server by using a remote procedure call (RPC) connection or a secure HTTP (HTTPS) connection, you receive one of the following error messages:

  • There is a problem with the proxy server’s security certificate. The name on the security certificate is invalid or does not match the name of the target site. Outlook could not connect to this server (error code 10).
  • There is a problem with the proxy server’s security certificate. Nowhere in Outlook can connect to the proxy server (error code 10).
  • There is a problem with the proxy server’s security certificate. The security certificate is not from a trusted certificate authority. Outlook could not connect to this server (error code 10).

To understand further, let’s analyze the causes of the error one by one:

Why does Outlook say it cannot connect to the proxy server?

A few main reasons for the error “Outlook cannot connect to this server” are listed.

  • When you try to connect to a server and the connection requires a certificate authority.
  • Can’t leverage Certificate Authority at all
  • Certificate may be invalid or rejected
  • The website name does not match the name in the certificate
  • A third-party add-in or a third-party browser add-in is blocking access, or sometimes it is caused by corrupted Outlook files.

How to fix proxy server security certificate in Outlook?

Mentioned below are few ways to fix Outlook cannot connect to the proxy server error:

Verify certificate:

If the certificate name is invalid or Outlook cannot connect with the proxy server, two things should be thoroughly verified. First, the expiration date of the certificate, and second, the information mentioned in the subject field must match the site name.

Follow the steps below to check the certificate:

  1. Open Internet Explorer, connect to any secure and trustworthy server, and press Enter. Or enter https://www.[servername].com/rpc” in the browser’s address bar and press Enter. Then, connect with the RPC server.
  2. Once you find the padlock  icon in the lower right corner of your web browser, double-click it and select the Details  tab.
  3. Note the information from the Valid to and  Subject  fields.

If the dates provided under the details are accurate and the subject matches the site name, your certificate is up to date. If not, the certificate has expired, or you need to change the website name.

Install trusted certificates:

If you encounter an error notification stating that the security certificate is not from a trusted authority, or was not added to the Microsoft Management Console (Microsoft Management Console that contains all Certificates snap-ins).

Here are the steps to install a trusted root certificate:

  1. When the Certificate dialog box opens, click the Install Certificate  option and  Next  to continue.
  2. Check the box Place all certificates in the following stores.
  3. Now, click Browse  to select Trusted Root Certification Authorities and click OK. Click Next  to proceed further.
  4. Wait for the process to complete. When finished, click the Finish  button.

If the error persists, and you cannot get rid of it, try adding the Certificates snap-in to the MMC.

  1. Open Run (Windows + R)  and type click 
  2. Go to File > Add/Remove Snap-in.
  3. Select a certificate, and then choose Add.
  4. Click on My User Accounts.
  5. Choose Add  again, this time choosing Computer Account .
  6. 将新证书从Certificates-Current UserTrusted Root Certification Authorities 进入 Certificates (Local Computer) > Trusted Root Certification Authorities.

Turn off third-party add-ons:

Third-party add-ins are responsible for most Outlook errors including proxy server errors,  0x80040154  and others. If the error shows that the security certificate is invalid or does not match the name of the target site, follow the steps below to achieve the desired result:

  1. If Outlook is running in your system, close it and press the Win + R keys to open the Run window.
  2. Type ” exe /safe ” in the “Run” search bar and click OK .

Fix Outlook Proxy Server Error

  1. If you can run the mod safely without any issues, it means that the problem is with a third-party add-on.
  2. To disable third-party add-ins, go to Options at the top of the File Outlook screen.
  3. Choose Options from the File menu, then click  Add-ins .
  4. Find the Admin box and click COM Add-ins .
  5. Click Go to develop further.
  6. Do you see a checkbox next to Third-party add-ons? be clear
  7. Restart Outlook.

If none of the above solutions successfully fixed it for you, the problem might be with your Outlook files. Your Outlook PST or OST may get corrupted due to some malware intrusion or any other reasons.

Outlook PST files are stored on a network server. Your PST file may become inaccessible when your PST file is located on the server that is experiencing issues. Also, it can even corrupt your PST file if the server goes down.

In such cases, you can make use of  SFWare Outlook Repair Tool  to repair any corrupted Outlook files. There is no harm in trying all possible solutions to get the app working.

SFWare Outlook PST Repair Tool is a dedicated tool for repairing any damaged or damaged Outlook data files . Built-in features like Normal Scan and Smart Scan help to repair complex PST file issues easily. The tool works in read-only mode to ensure that no harm will be done to generate healthy PST files . Download the software now and fix PST file corruption in few easy steps .

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in conclusion

As quoted above in the article, “Outlook cannot connect to the proxy server” is an error related to the exchange server. With the help of the methods above, you can try to fix the error and get Outlook running normally. If your Outlook file is corrupted, you can always rely on SFWare Outlook Repair Tool for hassle-free assistance.

Frequently Asked Questions:

How to fix security certificate error in Outlook?

First, you need to verify the certificate and install a trusted root certificate. If the error persists and you cannot get rid of it, try adding the Certificates snap-in to the MMC. You can follow the above detailed steps to fix security certificate error in Outlook

How do I recover my certificate in Outlook?

Below are the steps to restore the default SSL certificate and private key. Go to Control Panel >> System >> Security >> Certificates and Private Keys. Now click Revert to Default. A confirmation message will appear >> OK.

How can I find my certificate in Outlook?

Follow the steps to view the certificate in Outlook. First, on the File tab >> click Options >> click Trust Center. >> Click Email Security. Go to Encrypted Email >> Click Settings >> Under Certificates and Algorithms >> Click Select. Now, click on the desired certificate and then click on View Certificate.

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