Unable to login to F5 Big-IP CLI console after data centre move

Looking around in the support database, it seems like these symptoms have come up when the BIG-IP is configured for an unavailable TACACS server authentication on the CLI. I'd review the settings for external authentication and make sure the authentication servers that were available at the old DC are also at the new DC. The same error might be presented if other types of external auth are improperly configured, so be sure to check all of the "auth" config stanzas, and also the DNS.

You can find these in one of the config files, /config/bigip*.conf

auth tacacs /Common/system-auth { 
  protocol ip secret mysecretpassword
  servers { my-lost-server.local 10.10.5.5 10.20.5.5 }
  service ppp 
}

To break into your lost password BIG-IP, follow this procedure:

https://my.f5.com/manage/s/article/K35811337