weblogic: The admin server failed to authenticate the identity of the user weblogic starting the managed server

the problem: starting up a weblogic managed server gives you the following error:

<Jan 15, 2014 10:32:42 AM HST> <Error> <Configuration Management> <BEA-150021> 
<The admin server failed to authenticate the identity of the user weblogic starting the managed server. The reason for the error is .>
<Jan 15, 2014 10:32:42 AM HST> <Error> <Configuration Management> <BEA-150001> 
<An error occurred while connecting to the admin server to bootstrap through URL: http://localhost:7001/bea_wls_management_internal2/Bootstrap, user: weblogic
weblogic.management.configuration.ConfigurationException: [Configuration Management:150021]The admin server failed to authenticate the identity of the user weblogic starting the managed server. The reason for the error is .
at weblogic.management.provider.internal.BootStrapHelper.getBootStrapStruct(BootStrapHelper.java:128)
at weblogic.management.provider.internal.RuntimeAccessImpl.onConnect(RuntimeAccessImpl.java:597)
at weblogic.server.channels.RemoteChannelServiceImpl$2.run(RemoteChannelServiceImpl.java:302)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:256)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:221)
>

the cause: this can be caused by changing the weblogic password and your boot.properties file hasn’t been updated OR weblogic hasn’t picked up the change in that file yet.

the fix: 

1. shutdown the server giving the error

2. edit the boot.properties located in the server’s security directory to contain (in plain text) the username and password –>  <domain>/servers/<server>/security/boot.propertiesExample:
   username=weblogic
   password=password123

3. start the managed server through the startManagedServer script in the <domain>/bin directory — this will ensure the boot.properties file gets encrypted and registered

4. the server should startup correctly without complain if the credentials in the boot.properties are correct. you can then shutdown the server and start it up through the node manager if you wish.