Engineer-written guides
Fix Software Errors, Fast.
Practical troubleshooting guides for 8423+ real-world errors in OpenAI, Docker, Kubernetes, AWS, Python, Linux and more.
AWS 5 articles
- AWS AccessDeniedException: User is not authorized IAM user or role lacks the required permission for the requested action CLI / SDK
- AWS InvalidClientTokenId: The security token is invalid AWS credentials are malformed, expired, or for the wrong region CLI / SDK
- AWS ThrottlingException: Rate exceeded AWS API calls exceeded the allowed request rate for the account SDK / API
- AWS S3 403 Forbidden – Access Denied S3 bucket policy or ACL blocks the requested operation S3 / CLI
- AWS EKS You must be logged in to the server (Unauthorized) kubectl cannot authenticate to the EKS cluster EKS / CLI
Docker 5 articles
- Docker container exited with code 1 Container process terminated with a general error CLI / runtime
- Docker OOMKilled – container killed due to out of memory The container exceeded its memory limit and was killed by the kernel runtime
- Docker permission denied while connecting to daemon socket Current user is not in the docker group or daemon is not running CLI
- Docker pull – image not found (manifest unknown) The specified Docker image or tag does not exist in the registry CLI
- Docker Error: port is already allocated The host port is already in use by another process or container CLI
Gemini 4 articles
- ResourceExhausted: 429 Quota Exceeded Google Gemini API free-tier quota exhausted API
- PermissionDenied: 403 Forbidden API key lacks permission or the model is restricted in your region API
- Unauthenticated: 401 API key invalid The provided Gemini API key is missing or malformed API
- BlockedBySafetySettings The response was blocked by Gemini content safety filters API
Git 4 articles
- Git merge conflict – Automatic merge failed; fix conflicts Two branches have incompatible changes to the same lines CLI
- Git error: failed to push some refs – remote contains work you do not have The remote branch has commits not in your local branch CLI
- Git warning: You are in 'detached HEAD' state HEAD points directly to a commit instead of a branch CLI
- Git error: Permission denied (publickey) SSH key is missing, not added to agent, or not registered on the remote CLI / SSH
GitHub Actions 3 articles
- GitHub Actions Error: secret not found or empty A workflow references a secret that is not defined in repo settings CI/CD
- GitHub Actions Error: Resource not accessible by integration The GITHUB_TOKEN lacks required permissions for the action CI/CD
- GitHub Actions Error: The job running has exceeded the maximum execution time The workflow job exceeded the 6-hour (or custom) timeout limit CI/CD
HTTP 3 articles
- CORS Error: Access-Control-Allow-Origin missing or blocked The browser blocked a cross-origin request due to missing CORS headers browser / API
- HTTP 401 Unauthorized The request lacks valid authentication credentials API
- HTTP 403 Forbidden The server understood the request but refuses to authorise it API
Kubernetes 5 articles
- Kubernetes CrashLoopBackOff Pod keeps crashing and Kubernetes is backing off restart attempts cluster
- Kubernetes ImagePullBackOff Kubernetes cannot pull the container image from the registry cluster
- Kubernetes OOMKilled – pod terminated due to memory limit The container exceeded its memory limit and was killed by Kubernetes cluster
- Kubernetes pod stuck in Pending state Pod cannot be scheduled due to resource constraints or node issues cluster
- Kubernetes kubectl connection refused to API server kubectl cannot reach the Kubernetes API server CLI
Linux 5 articles
- Linux bash: Permission denied The current user lacks execute or read permission on the file shell / CLI
- Linux bash: No such file or directory The specified file or directory path does not exist shell / CLI
- Linux bind: Address already in use (EADDRINUSE) A process is already listening on the requested port networking / runtime
- Linux No space left on device (ENOSPC) The disk partition has no remaining free space filesystem
- Linux process Killed (signal 9 / SIGKILL) The OOM killer or a user terminated the process forcefully process management
MongoDB 2 articles
MySQL 3 articles
- MySQL ERROR 1045: Access denied for user Wrong username, password, or host not allowed in MySQL user grants database
- MySQL ERROR 1049: Unknown database 'X' The specified database does not exist on this MySQL server database
- MySQL ERROR 2003: Can't connect to MySQL server on 'host' MySQL server is not running or the host/port is incorrect database
Next.js 2 articles
Nginx 3 articles
- Nginx 502 Bad Gateway Nginx received an invalid response from the upstream server reverse proxy
- Nginx 504 Gateway Timeout The upstream server did not respond in time reverse proxy
- Nginx error: permission denied while connecting to upstream SELinux or filesystem permissions block Nginx from reaching the socket server / Linux
Node.js 4 articles
- Node.js Error: ENOENT no such file or directory Node cannot find the file or directory specified in the operation runtime
- Node.js Error: EADDRINUSE port already in use The port your app is trying to bind to is already occupied runtime / networking
- Node.js Error: Cannot find module 'X' The required Node module is missing from node_modules runtime
- Node.js FATAL ERROR: Reached heap limit – JavaScript heap out of memory The Node.js process exceeded its default V8 heap size limit runtime
OpenAI 6 articles
- RateLimitError: 429 Too Many Requests OpenAI API rate limit exceeded for your current plan tier API
- AuthenticationError: 401 Unauthorized Invalid or missing OpenAI API key API
- ServiceUnavailableError: 503 Service Unavailable OpenAI API is temporarily overloaded or down API
- InternalServerError: 500 Internal Server Error An unexpected error occurred on OpenAI's server side API
- InvalidRequestError: context_length_exceeded The prompt exceeds the maximum token limit for the model API
- BadRequestError: 400 Bad Request Malformed request body or invalid parameters sent to the API API
PostgreSQL 3 articles
- PostgreSQL: connection refused – could not connect to server PostgreSQL is not running, wrong port, or firewall is blocking the connection database
- PostgreSQL error: password authentication failed for user Wrong password or pg_hba.conf rejects the authentication method database
- PostgreSQL FATAL: remaining connection slots are reserved The database has hit its max_connections limit database
Python 26 articles
- Python ModuleNotFoundError: No module named 'X' The imported module is not installed in the active Python environment runtime
- Python ImportError: cannot import name 'X' from 'Y' The specific name being imported does not exist in the target module runtime
- Python AttributeError: object has no attribute 'X' Trying to access a method or property that doesn't exist on an object runtime
- Python TypeError: unsupported operand type(s) An operation is applied to objects of incompatible types runtime
- Python RecursionError: maximum recursion depth exceeded A function calls itself too many times without a proper base case runtime
- SyntaxError: invalid syntax This error occurs when the Python interpreter finds a grammatical mistake in the code. runtime, build, CLI
- IndentationError: expected an indented block This error signifies incorrect indentation, which is crucial for Python's block structure. runtime, build, CLI
- NameError: name 'X' is not defined This error indicates that a variable or function name was used before it was assigned or defined. runtime
- ValueError: invalid literal for int() with base 10: 'X' This error occurs when a function receives an argument of the correct type but an inappropriate value, such as trying to convert a non-numeric string to an integer. runtime
- IndexError: list index out of range This error means you are trying to access an index of a sequence (like a list or tuple) that does not exist. runtime
- KeyError: 'X' This error occurs when you try to access a dictionary key that does not exist. runtime
- ZeroDivisionError: division by zero This error happens when an attempt is made to divide a number by zero. runtime
- FileNotFoundError: [Errno 2] No such file or directory: 'X' This error indicates that a file or directory being accessed does not exist at the specified path. runtime, filesystem
- OSError: [Errno 13] Permission denied: 'X' This error means the operating system denied access to a file or resource, often due to insufficient permissions. runtime, filesystem, CLI
- StopIteration This error signals that an iterator has no more items to produce. runtime
- MemoryError This error occurs when an operation runs out of available memory. runtime
- KeyboardInterrupt This error is raised when the user interrupts program execution, typically by pressing Ctrl+C. runtime, CLI
- UnboundLocalError: local variable 'X' referenced before assignment This error occurs when a local variable is accessed within a function before it has been assigned a value. runtime
- AssertionError This error is raised when an assert statement fails, indicating an unexpected condition in the code. runtime, testing
- RuntimeError: dictionary changed size during iteration This error occurs when a dictionary is modified (items added or removed) while it is being iterated over. runtime
- IOError: [Errno 22] Invalid argument This error signifies that an I/O operation received an argument that is invalid or inappropriate for the operation. runtime, filesystem
- TypeError: 'NoneType' object is not subscriptable This error means you are trying to access an item from an object that is None, as if it were a sequence or mapping. runtime
- TypeError: object is not callable This error occurs when you try to call something that is not a function or method, like a variable assigned to a non-callable object. runtime
- BrokenPipeError: [Errno 32] Broken pipe This error indicates that one end of a pipe (e.g., a connection to another process) has been closed while the other end is still trying to write to it. runtime, inter-process communication
- SystemExit: 1 This error is raised by the sys.exit() function and indicates that the program is exiting, often with an error status. runtime, CLI
- AttributeError: module 'X' has no attribute 'Y' This error means you are trying to access a non-existent attribute or member of a Python module. runtime
React 2 articles
- React Hydration Error: server HTML does not match client render The server-rendered HTML differs from what React renders on the client runtime / SSR
- React Error: Invalid hook call – Hooks can only be called inside a function component A React hook is called outside of a component or inside a class component runtime
Redis 2 articles
SSL/TLS 3 articles
- SSL certificate has expired The TLS certificate's notAfter date is in the past HTTPS / networking
- SSL certificate error: self-signed certificate in certificate chain The certificate is not issued by a trusted CA HTTPS / networking
- SSL handshake failure: TLSv1 Alert Client and server cannot agree on a TLS version or cipher suite HTTPS / networking
Terraform 2 articles
TypeScript 3 articles
- TypeScript TS2345: Argument of type 'X' is not assignable to parameter of type 'Y' A value of the wrong type is passed to a function parameter compile
- TypeScript TS2339: Property 'X' does not exist on type 'Y' Accessing a property that is not defined in the type declaration compile
- TypeScript TS2307: Cannot find module 'X' or its corresponding type declarations The module is missing or has no @types package installed compile
npm 3 articles
- npm ERR! ERESOLVE unable to resolve dependency tree npm cannot find a compatible version for a dependency CLI
- npm ERR! EACCES permission denied npm lacks write permission to the global node_modules directory CLI
- npm ERR! 404 Not Found – package not found in registry The package name does not exist in the npm registry CLI