How to fix "The WinRM service cannot process the request because the wsman:ConnectionRetry element in the DeliverTo is invalid."

Description

This error occurs in Microsoft Windows environments when using Windows Remote Management (WinRM) for event forwarding, remote scripting, or WS-Management sessions. It specifically indicates a schema validation failure within the SOAP request payload sent to the WinRM service.

The DeliverTo element in the WS-Eventing or WS-Management XML structure defines how and where notifications or responses should be delivered. Inside this structure, the wsman:ConnectionRetry element tells the service how many times or how frequently it should attempt to reconnect if a connection fails.

The WinRM service throws this error due to two primary reasons:

1. Invalid Value Data Types: The value provided inside the <wsman:ConnectionRetry> tags does not conform to the expected XML data type (such as an integer or specific duration format).
2. Schema Mismatch (WS-Management Version Compatibility): The client application generating the request is using an outdated or non-standard implementation of the WS-Management protocol that introduces syntax elements that the receiving Windows WinRM service cannot parse or explicitly rejects.

Step-by-Step Fixes

Depending on whether you are running an event subscription, executing custom PowerShell scripts, or managing third-party monitoring tools, use the following methods to resolve the issue.

Method 1: Modify or Remove the ConnectionRetry Parameter in Event Subscriptions

If you are using Windows Event Forwarding (WEF), the retry element is often defined inside the subscription configuration.

1. Open PowerShell as an Administrator.
2. Export your current subscription configuration to an XML file by running:

   wecutil gs "YourSubscriptionName" /f:xml > C:\subscription.xml

3. Open C:\subscription.xml using Notepad or an XML editor.
4. Search for the <wsman:ConnectionRetry> tag.
5. Verify its value. If it contains invalid characters, symbols, or letters, change it to a valid integer (for example, 5).
6. If the parameter is not strictly required by your workflow, delete the entire <wsman:ConnectionRetry>...</wsman:ConnectionRetry> block from the file.
7. Save and close the file.
8. Update the subscription in Windows using the modified XML file:

   wecutil ss /c:C:\subscription.xml

Method 2: Update Third-Party Monitoring Agents or Management Software

If this error occurs when a Linux server, a monitoring tool (like Nagios, Zabbix, SolarWinds), or a backup system connects to your Windows machine, the client software is sending malformed XML headers.

1. Identify the software initiating the remote connection to the Windows machine.
2. Check the vendor documentation for known WinRM compatibility patches.
3. Update the management agent, SDK, or command-line utility on the client side to the latest version.
4. If you are using a custom Python script (e.g., via pywinrm), ensure your libraries are updated, as older versions had formatting bugs with certain WS-Man extensions.

Method 3: Restart and Reset the WinRM Service Configuration

Corrupted WinRM listeners or conflicting configuration policies can cause parsing errors. Resetting the service ensures standard parameters are applied.

1. Press the Windows Key + X and select Terminal (Admin) or Command Prompt (Admin).
2. Stop the WinRM service by typing:

   net stop winrm

3. Reset the WinRM default configuration parameters back to factory settings:

   winrm quickconfig -q

4. Check the status of your listeners to ensure they are clean:

   winrm e winrm/config/listener

5. Start the WinRM service again:

   net start winrm

Method 4: Adjust WSman Retry Registry Values (For Advanced Environments)

If group policies or registry configurations are pushing strict or corrupt WS-Management delivery settings, you can check the registry.

1. Press Windows Key + R, type regedit, and hit Enter to open the Registry Editor.
2. Navigate to the following path: HKEY LOCAL MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WSMAN\
3. Look for any subkeys related to Client or Service configurations that define custom retry profiles.
4. Ensure no string values (REG SZ) are assigned where DWORD values are expected for retry counts.
5. Close the Registry Editor and reboot the computer to apply changes.