When first enabling security on an Aerospike cluster, you will need to authenticate with the default username/password before being able to connect and configure your required users.
The Aerospike default username/password is admin/admin. It is of course strongly recommended to immediately change the password or even create a different admin user and remove the default one. Nodes subsequently added to the cluster will synchronize the user/roles from other nodes through the system meta data channel.
SECURITY DEFAULT USERNAME PASSWORD