I was using EPO 5.1.0 and tried updating it to 5.1.1
The installation failed and the setup rolled back.
After failed update, I can't login to EPO console.
Error creating bean with name 'core.extensionInstaller' defined in resource loaded from byte array: Cannot resolve reference to bean 'core.db' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'core.db' defined in resource loaded from byte array: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [com.mcafee.orion.core.db.base.MfsDatabase]: Constructor threw exception; nested exception is java.lang.IllegalStateException: Cannot initialize database object: check database configuration in /core/config
PluginManager was null!
I tried restarting McAfee services but "McAfee ePolicy Orchestrator 5.1.0 Application Server" and "McAfee ePolicy Orchestrator 5.1.0 Server" fail to start.
I also cannot open the console now.
I had the same issue with my test epo after my admin account continued to lock out. I realized that the service account I used for my SQL database was linked to this domain admin account.
So I followed Avinash Dasari advice and tried getting to: https://hostname:8443/core/config . Once in here (and with my domain account unlocked) I reset the password in the field to update it, test my connection (which was successful) and applied my change.
In order for it to complete I had to restart the server; afterwards I was back into my epo and my domain account stopped locking out.
Hope this helps anything with a similar issue.