Error map
session save path Warning: session_start(): open(/var/lib/php/sessions/sess_x, O_RDWR) failed: Permission denied
PHP · 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)
HTTP 403 Forbidden
The server understood the request but refuses to authorize it — you (or the server process) are not allowed to access this resour…
macOS: Operation not permitted — Terminal/app lacks Full Disk Access (TCC privacy protection)
macOS privacy protection (TCC) blocked access to protected folders (Desktop, Documents, Downloads, Mail, Photos, external volumes…
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.
HTTP 401 Unauthorized
The request has no valid authentication credentials — you need to log in or send a valid token.
Warning: session_start(): Session cannot be started after headers have already been sent
session_start() ran after output was sent, so PHP can’t set the session cookie.
InvalidOperationException: Session has not been configured for this application or request
Code used HttpContext.Session, but session services/middleware aren’t registered — or UseSession runs after the endpoint that nee…
OAuth 2.0 Error: invalid_scope / insufficient_scope
The requested scope is unknown or not allowed for this client — or the token lacks the scope the API endpoint requires.
PERMISSION_DENIED: The caller does not have permission (insufficient permissions)
You are authenticated, but your identity isn’t allowed to perform this action on this resource.
System.UnauthorizedAccessException: Access to the path 'x' is denied
The process’s identity can’t read/write that file or folder — IIS app pool identity, container user, read-only attribute, or a di…
AWS: ExpiredToken — The security token included in the request is expired
Temporary AWS credentials (STS/SSO/assumed role) have expired.
AccessControlListNotSupported: The bucket does not allow ACLs
The upload sets an ACL (like public-read), but the bucket uses “Bucket owner enforced” Object Ownership, which disables ACLs.
Key Vault: (Forbidden) The user, group or application does not have secrets get permission on key vault
The caller authenticated but has no permission on the vault — missing access policy or RBAC role, or the vault’s firewall blocks…
Two steps away (36)
Git: Permission denied (publickey). fatal: Could not read from remote repository.
SSH authentication to GitHub/GitLab/Bitbucket failed — no key, wrong key, or the key isn’t added to your account.
AWS S3: AccessDenied (403) when calling GetObject / PutObject
An IAM policy, bucket policy, ACL/ownership setting, Block Public Access or KMS key policy denied the S3 request.
Linux: Permission denied
Your user (or the service user) lacks read/write/execute permission on a file, directory or one of its parents.
npm ERR! code EACCES — permission denied
npm can’t write to a directory — usually global installs into a root-owned folder.
Windows Error 0x80070005 (E_ACCESSDENIED): Access is denied
Windows refused an operation because the account or process lacks permission — seen in Windows Update, installers, Task Scheduler…
user is not in the sudoers file. This incident will be reported.
Your account isn’t allowed to use sudo.
MySQL ERROR 2002 (HY000): Can't connect to local MySQL server through socket
The client couldn’t reach the MySQL server — it isn’t running, or the client is looking for the socket/port in the wrong place.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host port.
Error: getaddrinfo ENOTFOUND host / Name or service not known
DNS lookup for the hostname failed — the name is wrong, doesn’t exist, or this machine can’t resolve it.
Kubernetes: ImagePullBackOff / ErrImagePull
The node can’t pull the container image — wrong name/tag, missing registry credentials, or registry unreachable.
Azure AD (Entra ID): AADSTS700016 Application not found in the directory
The client ID in your sign-in request doesn’t exist in the tenant you’re authenticating against.
HTTP 400 Bad Request
The server could not understand the request because its syntax, headers or body are malformed or invalid.
Warning: Cannot modify header information - headers already sent
You called `header()`, `setcookie()` or `session_start()` after output had already been sent to the browser.
CORS Error: No 'Access-Control-Allow-Origin' header is present
The browser blocked a cross-origin request because the server’s response didn’t include the CORS headers allowing your site’s ori…
HTTP 411 Length Required
The server refuses a request with a body but no Content-Length header.
ASP.NET Core: The CORS protocol does not allow specifying a wildcard (any) origin and credentials at the same time
The CORS policy uses AllowAnyOrigin() together with AllowCredentials(), which browsers forbid.
AmbiguousMatchException: The request matched multiple endpoints. Matches: X, Y
Two controller actions or minimal API endpoints have the same route and HTTP method.
ASP.NET Core: The antiforgery token could not be decrypted / The required antiforgery cookie is not present (400 Bad Request)
Form POST failed antiforgery validation — the token is missing, the cookie is missing, or Data Protection keys changed so old tok…
OAuth 2.0 Error: invalid_grant
The authorization code, refresh token or credentials sent to the token endpoint are invalid, expired, already used or were issued…
OAuth 2.0 Error: invalid_client
The OAuth server couldn’t authenticate your application — wrong client ID/secret, wrong auth method, or the client doesn’t exist…
java.nio.file.AccessDeniedException: /path
The OS denied a file operation to the Java process.
Azure: AuthorizationFailed — The client does not have authorization to perform action
The signed-in identity (user, service principal or managed identity) lacks an Azure RBAC role for that action on that scope.
Azure Storage: AuthorizationPermissionMismatch (403) — This request is not authorized to perform this operation using this permission
You’re accessing blob/queue data with Microsoft Entra ID, but the identity has only management roles (Owner/Contributor) — not a…
WordPress: Sorry, you are not allowed to access this page.
Your user role lacks the capability for that admin screen — or the database table prefix / user capabilities are out of sync afte…
Error: ENOENT: no such file or directory
A file or directory the program tried to open doesn’t exist at that path.
java.io.FileNotFoundException: config.properties (No such file or directory)
Java couldn’t open the file — wrong path relative to the working directory, missing file, or a classpath resource read as a file.
java.nio.file.NoSuchFileException: /path/file
An NIO Files operation targeted a path that doesn’t exist.
kubectl: The connection to the server localhost:8080 was refused — did you specify the right host or port?
kubectl has no usable kubeconfig, so it falls back to localhost:8080 — or the cluster API server is unreachable.
AWS: Unable to locate credentials / Could not load credentials from any providers
The AWS CLI/SDK found no credentials in any place it looks — env vars, profile files, SSO cache or an instance/task role.
AWS: SignatureDoesNotMatch / InvalidClientTokenId — the request signature we calculated does not match
AWS rejected the request signature — wrong secret key, wrong region, clock skew, or a presigned URL used differently from how it…
AWS S3: NoSuchKey / NoSuchBucket — The specified key/bucket does not exist
S3 found no object at that key (or no bucket with that name in the region/account you’re calling).
NotAllowedError: Failed to execute 'writeText' on 'Clipboard': Document is not focused.
The Clipboard API refused to write — the page isn’t focused, there was no user gesture, or the context isn’t secure.
Error: listen EACCES: permission denied 0.0.0.0:80
Node isn’t allowed to bind that port — ports below 1024 need root on Linux/macOS, and some Windows ports are reserved.
Error: EPERM: operation not permitted, rename / unlink
The OS refused a file operation — on Windows usually because another process (antivirus, editor, indexer) has the file locked.
Error: spawn EACCES
Node tried to execute a file that isn’t executable (missing +x permission) or isn’t a program.
Laravel: The stream or file "storage/logs/laravel.log" could not be opened in append mode: Failed to open stream: Permission denied
The web server can’t write to Laravel’s storage or bootstrap/cache directories.
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