Error map
Redis::CannotConnectError (Sidekiq/Rails) Redis::CannotConnectError: Error connecting to Redis on localhost:6379 (Errno::ECONNREFUSED)
Ruby / Rails · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
Redis: (error) NOAUTH Authentication required. / WRONGPASS invalid username-password pair or user is disabled
The server requires a password (or ACL user) and the client sent none or the wrong one.
Redis: Error: read ECONNRESET / redis.exceptions.ConnectionError: Connection reset by peer after idle time
A middlebox or Redis closed an idle connection, and the pooled client reused it.
Redis: Client id=12 addr=10.0.0.5:51234 scheduled to be closed ASAP for overcoming of output buffer limits
A client (often a slow subscriber or a replica) couldn't read data fast enough, so Redis disconnected it to protect memory.
Redis: evicted_keys growing — keys vanish unexpectedly because maxmemory is reached and a volatile/allkeys eviction policy is active
Redis removed keys to stay under `maxmemory` according to the eviction policy.
Redis: INFO memory — mem_fragmentation_ratio:2.8 (RSS much larger than used_memory)
The process uses far more RSS than the data size, due to allocator fragmentation or deleted-but-not-returned memory.
Redis ACL: (error) NOPERM this user has no permissions to run the 'flushall' command or its subcommand
The authenticated ACL user lacks permission for that command or key pattern.
Redis: (error) BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE
A long-running Lua script (or function) blocks the single-threaded server, so other commands are rejected.
Redis client: Error: Command timed out / redis.exceptions.TimeoutError: Timeout reading from socket
The client waited longer than its timeout for a Redis reply.
Docker: Redis data gone after container restart — dump.rdb not persisted to a volume
The container's `/data` isn't mounted to a volume, so snapshots vanish when the container is recreated.
Redis: (error) ERR CONFIG SET failed (possibly related to argument 'maxmemory') - can't set immutable config
`CONFIG SET` rejected the parameter — it is immutable at runtime, invalid, or disabled by the hosting provider.
Redis: Could not connect to Redis at 10.0.0.5:6379: Connection timed out
Redis only listens on localhost by default, so remote clients time out or are refused.
Redis replica: (error) MASTERDOWN Link with MASTER is down and replica-serve-stale-data is set to 'no'
A replica lost its connection to the master and refuses to serve possibly stale data.
Two steps away (36)
ReplyError: NOAUTH Authentication required.
The Redis server requires a password (or ACL user) but the client didn’t authenticate.
pull access denied for image, repository does not exist or may require 'docker login'
Docker couldn’t pull the image: the name or tag is wrong, the repository is private and you’re not logged in, or it doesn’t exist…
unauthorized: authentication required (docker push / pull)
The registry needs credentials for this operation and the request had none or had expired ones.
Laravel: SQLSTATE[HY000] [2002] Connection refused (SQL: select * from sessions) / php_network_getaddresses: getaddrinfo failed
Laravel can't open a network connection to the database host and port from `.env`.
Laravel: Predis\Connection\ConnectionException: Connection refused [tcp://127.0.0.1:6379] / RedisException: Connection refused
Laravel can't connect to Redis, which it uses for cache, sessions or queues.
Redis: Error: connect ECONNREFUSED 127.0.0.1:6379 / Could not connect to Redis at 127.0.0.1:6379: Connection refused
Nothing is listening on the Redis host/port your client uses.
Kubernetes: OOMKilled (exit code 137)
The container used more memory than its limit, and the kernel killed it.
java.lang.OutOfMemoryError: Java heap space
The JVM ran out of heap memory and garbage collection couldn’t free enough.
Segmentation fault (core dumped)
A program accessed memory it wasn’t allowed to, and the kernel killed it with SIGSEGV (exit code 139).
Killed / Out of memory: Killed process (Linux OOM killer)
The kernel ran out of memory and killed a process to recover — the program just prints “Killed” (exit code 137).
FATAL ERROR: Reached heap limit Allocation failed - JavaScript heap out of memory
The V8 heap hit its limit — a large build (webpack, tsc, Next.js) needs more memory, or the app leaks.
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added
More than 10 listeners were added to one event — often a leak where listeners are added repeatedly.
Redis: OOM command not allowed when used memory > 'maxmemory'
Redis reached its maxmemory limit and the eviction policy (noeviction) refuses new writes.
Redis: # Can't save in background: fork: Cannot allocate memory / WARNING overcommit_memory is set to 0!
Redis couldn't fork to write an RDB/AOF snapshot because the OS refused to allocate memory.
Redis: SLOWLOG GET shows KEYS * taking 1500000 microseconds — server blocked
Redis is single-threaded; one slow command delays everything else.
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
The docker CLI can’t talk to the Docker engine — it isn’t running, or your user can’t access the socket.
user is not in the sudoers file. This incident will be reported.
Your account isn’t allowed to use sudo.
java.nio.file.AccessDeniedException: /path
The OS denied a file operation to the Java process.
WRONGTYPE Operation against a key holding the wrong kind of value
A Redis command was used on a key of a different type (e.g. HGET on a string key).
Redis: DENIED Redis is running in protected mode because protected mode is enabled and no password is set for the default user
Redis refuses connections from non-local clients when it has no password and is bound to all interfaces.
Redis: Error: write EPROTO ... SSL routines:ssl3_get_record:wrong version number / Connection reset by peer (TLS vs plaintext)
The client and server disagree about TLS — plaintext client to a TLS port, or TLS client to a plaintext port.
Laravel: Symfony\Component\ErrorHandler\Error\FatalError: Maximum execution time of 30 seconds exceeded
A web request ran longer than PHP's `max_execution_time` and was killed.
Laravel: Symfony\Component\Process\Exception\ProcessTimedOutException: The process "npm run build" exceeded the timeout of 60 seconds
A subprocess launched via the `Process` class or `Process::run()` exceeded its allowed time.
Laravel: Illuminate\Http\Client\ConnectionException: cURL error 28: Operation timed out after 30001 milliseconds with 0 bytes received
The Laravel `Http::` client waited for a response longer than its timeout and gave up.
Redis: MISCONF Redis is configured to save RDB snapshots, but it's currently unable to persist to disk
Redis couldn’t write its RDB snapshot (disk full, permissions, fork failed), so it blocks writes to protect data.
Laravel Sail: SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo for mysql failed: Temporary failure in name resolution
Commands run outside the Sail container (on the host) try to resolve the Docker service name `mysql`, which only exists inside th…
Redis: # Failed opening the temp RDB file temp-1234.rdb (in server root dir /var/lib/redis) for saving: Permission denied
Redis can't write its snapshot file to the configured directory.
Laravel: .env changes ignored / env('X') returns null after php artisan config:cache
After `config:cache`, Laravel no longer reads `.env`, so `env()` calls outside config files return null and edits to `.env` have…
Redis: Closing idle client / Connection closed by server after timeout 300
Redis' `timeout` directive closes connections idle longer than N seconds.
Redis: (error) ERR unknown command 'JSON.GET', with args beginning with: / unknown command 'FT.SEARCH'
The server doesn't know the command — wrong name, newer Redis version, or a missing module.
Error response from daemon: network X not found
The container or Compose project refers to a Docker network that doesn’t exist (any more).
Error response from daemon: Pool overlaps with other one on this address space
Docker tried to create a network whose subnet clashes with an existing Docker network (or a VPN/host route).
driver failed programming external connectivity on endpoint: iptables: No chain/target/match by that name
Docker’s iptables rules were wiped (firewalld/ufw reload, iptables flush) while Docker was running, so it can’t publish ports.
Redis: READONLY You can't write against a read only replica
The client is connected to a replica (or a failed-over node) and tried to write.
Redis: (error) LOADING Redis is loading the dataset in memory
Redis is starting and still reading its RDB/AOF, so it rejects commands temporarily.
Redis: Client id=7 scheduled to be closed ASAP for overcoming of output buffer limits (replica) / MASTER <-> REPLICA sync: Timeout
A replica can't finish the initial sync because the master's replication buffer fills up or the transfer times out, so it restart…
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