Redis 'NOAUTH Authentication required' or 'WRONGPASS invalid username-password pair or user is disabled'. How do I pass credentials correctly from redis-cli and client libraries?

Cause: the Redis server requires authentication (requirepass, or ACL users since Redis 6) and the client either didn't authenticate (NOAUTH) or sent the wrong user/password, or the ACL user is disabled (WRONGPASS). Common triggers: a managed Redis (or a hardened config) that requires a password while the app connects without one; Redis 6+ ACLs where the password belongs to a named user but the client only sends a password (which authenticates as the 'default' user); special characters in the password breaking a redis:// URL; or a password changed on the server but not in the app's environment. Fix: 1. Test from redis-cli: redis-cli -h <host> -p <port> --user <user> --askpass (or AUTH <user> <password> after connecting); add --tls for TLS endpoints. A plain AUTH <password> authenticates as the default user. 2. In client URLs use redis://<user>:<password>@host:port/0 (rediss:// for TLS), URL-encoding special characters in the password; with only a password, redis://:<password>@host:port. 3. In libraries, set username and password explicitly (e.g. redis-py Redis(host=..., username=..., password=...), node-redis createClient({ username, password, url })), and read them from environment variables or a secret manager. 4. On the server, check the user exists and is enabled with ACL LIST / ACL GETUSER <user> (needs admin rights): it must be 'on', have the password, and allow the commands and keys your app uses. 5. Never disable authentication or bind an unauthenticated Redis to a public interface to make the error go away; exposed open Redis instances are routinely abused. Verify: redis-cli with the same credentials returns PONG to PING, and the application connects without NOAUTH/WRONGPASS errors. Sources: https://redis.io/docs/latest/commands/auth/ https://redis.io/docs/latest/operate/oss_and_stack/management/security/acl/