Error [Management:141191]The prepare phase of the configuration update failed with an exception

An error occurred during activation of changes, please see the log for details.
Message icon – Error [Management:141191]The prepare phase of the configuration update failed with an exception:
Solutions-
-> First thing never try to delete any managed server which is up and running.First shut down and then closed it.

Follow below steps to get rid of this error

-> Stop the Admin Server & Managed Servers which is up and running.
-> On your Admin Server cd to $WLS_HOME\user_projects\domains\base_domain.
-> Delete all files in pending and servers/domain_bak directory.
-> Start the Admin Server & Managed Servers.
-> Login the weblogic Admin Console and click on Release Configuration button.
-> Perform the same changes now.