Came across a strange issue when trying to add a new server to an existing farm. This had been working fine, but had started to fail almost immediately, after entering the server name and config DB, and entering the farm passphrase.
Turns out that it was caused by the session state service in the farm. Running this command in powershell:
Disable-SPSessionStateService
stopped the service. I was then able to run the config wizard again and added the server to the farm.
I can then re-enable the session state service.
Strange one i know, and i have no explanation as to cause.
This info was found here > https://social.technet.microsoft.com/forums/sharepoint/en-US/3a897619-df61-478d-822d-9f308f2c4b0f/sharepoint-config-wizard-failing-when-trying-to-join-a-new-server-to-existing-farm-with-error-failed
