An error occurs while running the auto-generated certificate renewal steps before the existing certificates expire. In Workflow Manager Farm, auto-generated certificate renewal fails.

While running the Auto-generated certificate Renewal steps before existing certificates expiry gets an error. Or Auto-generated Certificate Renewal fails in Workflow Manager Farm

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        ... Troubleshooting steps are
            Issue Description: 
                        When we perform the Auto-generated certificate Renewal steps. We are receiving the below error in Workflow Manager PowerShell.
Error:
    Auto-generated Certificate Renewal steps until we got the error.
        1. Open Workflow Manager PowerShell with "RunAsAccount"
        2. Run the below commands one after one.
        3. $Cert=convertto-securestring 'your password' -as plaintext -force;
                Note: update "Your Password" with your own password. This password is a passphrase/encryption key of the auto-generated certificate.
            The certificate will be generated based on the provided passphrase. You should keep it stored somewhere so you can use it if at any time you leave the farm and need to rejoin the farm. It is a one-time password at the time of generating the certificate.
        4. Run this step:
            Set-WFCertificateAutoGenerationKey-Key $CerKey
            We received the below error:
                Set-WFCertificateAutoGenerationKey-Key : Auto-Generation of certificate is not supported if the user has specific certificate thumbprints.
At line: Char:1
+Set-WFCertificateAutoGenerationKey-Key $CerKey
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Categoryinfo :NotSpecified (:)[Set-WFCertificateAutoGenerationKey], InvalidOperationException
+FullyWualifiedErrorId : System.InvalidOperationException,Microsoft.Workflow.Deployment.Commands.SetWFcerAutoGenerationKey
Troubleshooting steps
        1. While configure Workflow Manager with Custom Certificate after converted to Auto Generated Certificate.
        2. You have converted Auto Generated certificate to Custom Generated certificate when you have done last time certificate renewal.
        3. You are trying to renewal Auto-generated to New Custom certificate.
Solution Steps:
It is not possible to convert the custom Generated farm to Auto-generated certificate.
    Solution 1: Convert all existing certificates to Custom generated certificate if certificates are not Custom certificates. Proceed to Custom certificate renewal process or steps.
    Solution 2: Fresh Workflow Manager installation and configuration with Auto generated Certificate. (If you want to proceed with Autogenerted certificates needed