Outlook is unable to connect to the proxy server autodiscover

Some Microsoft Outlook customers after upgrading to Windows 11 began reporting they observed that some variations of Outlook together with Outlook for Microsoft 365 on their system that used to connect to the inside Exchange server now not works with the error message Outlook is unable to connect to the proxy server autodiscover. This publish supplies the most relevant options to the subject.

When this subject happens, you’ll obtain the following full error message with error code;

Microsoft Outlook
There is a problem with the proxy server’s security certificate.
Outlook is unable to connect to the proxy server autodiscover. (Error Code 80000000).

Outlook is unable to connect to the proxy server autodiscover

If you’re confronted with the Outlook is unable to connect to the proxy server autodiscover subject in your Windows 11/10 system, you’ll be able to strive our really helpful options beneath in no specific order to resolve the subject in your system.

  1. Initial guidelines
  2. Turn on TLS 1.0 on the native Windows 11 machine
  3. Add TLS 1.2 to the Exchange server
  4. Upgrade Exchange Server

Let’s check out the description of the course of concerned regarding every of the listed options.

1] Initial guidelines

Before you strive the options beneath, you are able to do the following and after every job see if Outlook can now connect to the proxy server autodiscover with out points:

  • Check Outlook consumer compatibility with Exchange server model. For instance, Microsoft 365 is not supported for Exchange 2010. If there’s one thing flawed once you use Microsoft 365 and Exchange 2010, incompatibility might also have an effect on this. In this case, set up the corresponding suitable Outlook consumer, reminiscent of Outlook 2013. In addition, to additional affirm whether or not the subject is associated to Outlook consumer, you’ll be able to strive logging in to Outlook Web App (OWA) and verify if it really works usually.
  • Check if Autodiscover service is working.  As the subject in focus is associated to Autodiscover, you’ll be able to comply with the directions in this post to take a look at Autodiscover connectivity utilizing the Outlook consumer. In addition, make certain your PC is not experiencing internet connectivity issues and that the Exchange server is not offline.
  • On-premises customers can run Microsoft Remote Connectivity Analyzer and Office 365 customers can run Microsoft Support and Recovery Assistant.
  • You can add your Exchange server’s MX identify/report to proxy exclusion listing and see if that helps. Also, you’ll be able to strive utilizing a VPN domestically in your community.

2] Turn on TLS 1.0 on the native Windows 11 machine

Turn on TLS 1.0-Registry Editor

This is extra of a workaround than an answer. However, this motion is not really helpful as a result of TLS 1.0 is retired and needs to be moved away from. Nevertheless, should you want a direct decision to the subject in spotlight you’ll be able to allow or activate TLS 1.0 through the registry on the native Windows 11 machine. Do the following:

Since this is a registry operation, it is really helpful that you simply back up the registry as mandatory precautionary measures. Once executed, you’ll be able to proceed as follows:

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindowsCurrentVersionInternet SettingsWinHttp
  • At the location, on the proper pane, double-click the DefaultSecureProtocols entry to edit its properties.

If the key is not current, right-click on the clean area on the proper pane after which choose New > DWORD (32-bit) Value to create the registry key after which rename the key accordingly and hit Enter.

  • Double-click on the new entry to edit its properties.
  • Type 00000080 in the Value knowledge area.
  • Click OK or hit Enter to save the change.
  • Next, soar to the registry path beneath and repeat the steps as above:
HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftWindowsCurrentVersionInternet SettingsWinHttp
  • Exit Registry Editor when executed.
  • Restart pc.

3] Add TLS 1.2 to the Exchange server

Windows 11 disables TLS 1.0 and TLS 1.1 by default and Exchange 2010 working on Windows 2008 R2 makes use of TLS 1.0. As reported in some circumstances, the subject in view began when the Windows 10 consumer machines have been upgraded to Windows 11 and the subject is solely observed on workstations related outdoors of the subnet the server is related to. That is all of the workstations related to the similar subnet as the server have been working effective after the Windows 11 improve, however all of the workstations outdoors of that subnet failed with proxy (Error Code 80000000).

This is a protected workaround to the subject and it requires the IT admin to add TLS 1.2 to the Exchange servers after which reboot the server afterwards. This works as a result of Windows 11 helps TLS 1.2 by default.

Below are the registry keys that can be added via Command Prompt:

[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsTLS 1.2Client]
  • Added DWORD: DisabledByDefault = 00000000 (0)
  • Added DWORD: Enabled = 00000001 (1)
[HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlSecurityProvidersSCHANNELProtocolsTLS 1.2Server]
  • Added DWORD: DisabledByDefault = 00000000 (0)
  • Added DWORD: Enabled = 00000001 (1)
  • Added DWORD: SystemDefaultTlsVersions = 00000001 (1)
  1. Added DWORD: SystemDefaultTlsVersions = 00000001 (1)

4] Upgrade Exchange Server

For instance, Exchange Server 2010 reached its finish of assist on October 13, 2020. For your higher person expertise, it is really helpful that you simply improve your Exchange server to a more recent model by your Internet Service Provider (ISP) or firm electronic mail server or IT administrator. After the Exchange improve, you’ll be able to improve and reinstall the newest model of Outlook consumer for Windows 11/10.

Hope this publish helps you!

Why does Outlook say Unable to connect to proxy server?

This subject might happen if a number of of the following circumstances are true:

  • The connection to the server requires a certification authority (CA).
  • You haven’t trusted the certification authority at the root.
  • The certificates could also be invalid or revoked.

What does proxy electronic mail imply?

A mail proxy server is a stand-alone machine that is positioned in entrance of the precise electronic mail server. The mail proxy server is personalized to present all or any of the following companies: Web based mostly electronic mail through IMAP.


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