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25 entries match these filters
- 0413 Fix: 502 Bad Gateway from Nginx Nginx is running but could not get a valid response from your application. Read the error log, check that the app is… Intermediate · Fixes an error · Linux Article Web servers & reverse proxies 15 Oct 2026
- 0375 Fix: disk full, find what is eating the space A Linux filesystem reports 100 percent used or No space left on device. Find the culprit with df and du, check journals,… Intermediate · Fixes an error · Linux Article Alerting & dashboards · Disks, LVM & filesystems 15 Oct 2026
- 0382 Fix: Resource not accessible by integration and other GitHub Actions permission errors A workflow step fails with Resource not accessible by integration, 403 on git push, or a GitHub CLI call is refused. The… Intermediate · Fixes an error · Any system Article GitHub Actions 15 Oct 2026
- 0324 Fix: psql: FATAL: Peer authentication failed On local socket connections PostgreSQL checks that your OS user name equals the database role. When they differ you get this error.… Intermediate · Fixes an error · Linux Article Install & connect · Security & access 15 Oct 2026
- 0325 Fix: SSL certificate problem: unable to get local issuer certificate curl, git, pip or npm cannot chain the server's certificate to a root they trust. Usual causes: a corporate proxy that re-signs… Intermediate · Fixes an error · Linux, macOS, Windows Article Common errors · Making requests · TLS & certificates 15 Oct 2026
- 0326 Fix: too many open files A process hit its file descriptor limit, usually 1024. Raise it for the shell, the systemd unit or the user, fix a… Intermediate · Fixes an error · Linux, macOS Article Performance & tuning · Processes & ports · Services & systemd 15 Oct 2026
- 0235 Fix: MongoServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017 Your app or tool tried to reach MongoDB on port 27017 and nothing accepted the connection. Usually mongod is not running, crashed… Intermediate · Fixes an error · Linux, macOS, Windows Article Administration · Basics 15 Oct 2026
- 0240 Fix: MISCONF Redis is configured to save RDB snapshots, but it’s currently unable to persist to disk Redis blocks writes because its last background snapshot failed. Find the cause in the log (full disk, permissions, failed fork), fix it,… Intermediate · Fixes an error · Linux Article Administration & persistence 15 Oct 2026
- 0209 Fix: FATAL: password authentication failed for user PostgreSQL reached the server and found a matching pg_hba.conf rule, but the password check failed. Usually a wrong password, a role without… Intermediate · Fixes an error · Any system Article Roles & administration · Security & access 15 Oct 2026
- 0210 Fix: FATAL: no pg_hba.conf entry for host The server received the connection but no pg_hba.conf rule matches this client address, user, database and SSL mode. Add or correct a… Intermediate · Fixes an error · Linux Article Install & connect · Security & access 15 Oct 2026
- 0226 Fix: ORA-12541: TNS:no listener The client reached the host but nothing was listening on that port. Start or fix the Oracle listener, or correct the host… Intermediate · Fixes an error · Linux, Windows Article Administration · Concepts & tools 15 Oct 2026
- 0227 Fix: ORA-01017: invalid username/password; logon denied Oracle rejected the login. Check the password (case-sensitive), that you connect to the right PDB service, and whether the account is locked… Intermediate · Fixes an error · Any system Article Administration · Security & access 15 Oct 2026
- 0186 Fix: Ansible UNREACHABLE! Failed to connect to the host via ssh Ansible could not open an SSH session to the host, so no task ran. The text after the colon tells you why:… Intermediate · Fixes an error · Linux, macOS Article Ansible · SSH & servers 15 Oct 2026
- 0143 Fix: CrashLoopBackOff in Kubernetes The container starts, exits, and Kubernetes waits longer before each restart. Read the previous container's logs and its exit code to find… Intermediate · Fixes an error · Linux Article Troubleshooting 15 Oct 2026
- 0161 Fix: Error from server (Forbidden): … is forbidden: User … cannot … in OpenShift oc refuses a command with Error from server (Forbidden). The message names the user, verb, resource and project. Learn how to read… Intermediate · Fixes an error · Any system Article Cluster administration · Troubleshooting 15 Oct 2026
- 0167 Fix: Job for nginx.service failed because the control process exited with error code systemctl prints this when a service's start command exits with an error. The real reason is in journalctl; for nginx it is… Intermediate · Fixes an error · Linux Article Networking & firewalls · Services & systemd 15 Oct 2026
- 0142 Fix: ImagePullBackOff and ErrImagePull in Kubernetes The pod cannot start because the node failed to pull the container image. Read the "Failed to pull image" event to see… Intermediate · Fixes an error · Linux Article Troubleshooting 15 Oct 2026
- 0111 Fix: can’t lock file ‘/var/lock/qemu-server/lock-VMID.conf’ – got timeout Another task is holding the VM's local lock file, so a new action timed out waiting for it. Find the running or… Intermediate · Fixes an error · Linux Article VMs & containers 15 Oct 2026
- 0127 Fix: “Requested operation is not valid: network ‘default’ is not active” A libvirt VM will not start because the virtual network it uses, usually the NAT network 'default', is stopped. Start the network… Intermediate · Fixes an error · Linux Article Basics 15 Oct 2026
- 0071 Fix: column “x” must appear in the GROUP BY clause or be used in an aggregate function PostgreSQL rejects a grouped query that selects a column with more than one possible value per group. Add the column to GROUP… Intermediate · Fixes an error · Any system Article Queries 15 Oct 2026
- 0089 Fix: 413 Request Entity Too Large A server or proxy rejected your request because its body is bigger than the configured limit. Find which layer set the limit,… Intermediate · Fixes an error · Any system, Linux Article Status codes · Web frameworks 15 Oct 2026
- 0041 Fix: CONFLICT (content): Merge conflict in … Two branches changed the same lines and Git cannot choose for you. Open the file, keep the right text, remove the markers,… Intermediate · Fixes an error · Any system Article Branching & rebasing · Common errors 15 Oct 2026
- 0042 Fix: fatal: refusing to merge unrelated histories Your local repository and the remote do not share a single commit, usually because both were started separately. Allow the one-time merge,… Intermediate · Fixes an error · Any system Article Common errors 15 Oct 2026
- 0054 Fix: Permission denied (publickey) The server refused every key your SSH client offered. Find out which key was offered, make sure its public half is on… Intermediate · Fixes an error · Linux, macOS, Windows Article Keys & config 15 Oct 2026
- 0027 Fix: SyntaxError: Cannot use import statement outside a module The file uses ES module import syntax, but Node or the browser is loading it as a classic script or CommonJS. Tell… Intermediate · Fixes an error · Any system Article Common errors · Node.js 15 Oct 2026