Articles in this section

See more

Disabling Transport Layer Security (TLS) 1.0 or Secure Socket Layer (SSL) 3.0 causes Outlook Web App (OWA) signature deployment via Exchange Web Services (EWS) to fail

Avatar
Exclaimer Support
  • Updated
Follow

Relevant Products: Signature Manager Outlook Edition

WARNING! The following products were discontinued on 30 September 2022:

- Exclaimer Signature Manager Outlook Edition

- Exclaimer Signature Manager Exchange Edition
 

The end of Support for these products is 30th September 2024.

For more information, please see the Discontinued Questions and Answers page.

Scenario

Even after you've disabled the Transport Layer Security (TLS) 1.0 or Secure Socket Layer (SSL) 3.0 in your Exchange environment for security compliance, you notice that the Outlook Web App (OWA) signatures fail to update.

The following error message is logged in the Exclaimer Application event logs, in Event Viewer, on the server or PC where the Exclaimer Signature Manager Outlook Edition is installed:

ERROR: 
Microsoft.Exchange.WebServices.Data.ServiceRequestException: The request failed. The underlying connection was closed: An unexpected error occurred on a receive. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a receive. ---> System.ComponentModel.Win32Exception: The client and server cannot communicate, because they do not possess a common algorithm.

Resolution

When you disable TLS 1.0 or SSL3, you need to ensure that TLS 1.2 is enabled for .NET Framework version 4.x.

To enable TLS 1.2 for .NET 4.x

  1. From Notepad.exe, create a text file and name it NET4X-UseSchannelDefaults.reg.

  2. Copy then paste the following text:

    Windows Registry Editor Version 5.00
    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]
    "SystemDefaultTlsVersions"=dword:00000001
    [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework\v4.0.30319]
    "SystemDefaultTlsVersions"=dword:00000001
  3. Save the NET4X-UseSchannelDefaults.reg file.

  4. Double-click the NET4X-UseSchannelDefaults.reg file.

  5. Click Yes to update your Windows Registry with these changes.

  6. Restart your computer for the change to take effect.

    Warning: Ensure that TLS 1.2 is enabled and configured on both the Exchange Server and the machine where the Signature Manager Outlook Edition is installed.

 

Note: 

The steps described above to enable TLS 1.2 for .NET 4.x are taken from part 2 of the following 3 part series of the Microsoft articles.

The following articles describe how to correctly enable and configure TLS 1.2 for EWS in an Exchange environment:

Part 1: https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Exchange-Server-TLS-guidance-part-1-Getting-Ready-for-TLS-1-2/ba-p/607649

Part 2: https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Exchange-Server-TLS-guidance-Part-2-Enabling-TLS-1-2-and/ba-p/607761

Part 3: https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Exchange-Server-TLS-guidance-Part-3-Turning-Off-TLS-1-0-1-1/ba-p/607898

 


Related articles