Windows Update Causes AXL Issue

After applying a Windows update, AXL appears to be inactive in CUCM, causing the SA-Announce Configuration Utility to display the following error.

Unable to execute AXL on CUCM. Please verify user has admin rights on CUCM and that the AXL web service is running on each listed CUCM.

This error is caused by a Microsoft change made to the Microsoft Secure Channel. Therefore, this cannot be fixed in the SA-Announce software.

  1. Open regedit.
  2. Locate this subkey:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\KeyExchangeAlgorithms\Diffie-Hellman
    If the Diffie-Hellman subkey doesn't exist, right-click on KeyExchangeAlgorithm, select New > Key, and type in Diffie-Hellman.
  3. Click on Diffie-Hellman.
  4. Click Edit > New > DWORD Value in the Registry Editor menu.
  5. Type ClientMinKeyBitLength for the name of the DWORD and press Enter.
  6. Right-click ClientMinKeyBitLength and click Modify.
  7. Type 00000200 in the Value data field and click OK.
  8. Exit Registry Editor.
  9. You may need to restart your computer for the changes to take affect.

(From Microsoft Support: https://support.microsoft.com/en-us/help/3061518/ms15-055-vulnerability-in-schannel-could-allow-information-disclosure-may-12,-2015)