Error map
NetworkOnMainThreadException android.os.NetworkOnMainThreadException
Android · layer 1, On your device
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)
Error Domain=NSURLErrorDomain Code=-1001 "The request timed out."
The server didn’t respond within URLSession’s timeout (60 s default) — slow server, unreachable host on this network, or a stalle…
DNS not working inside a Kubernetes pod (could not resolve host / nslookup: can't resolve)
Pods can’t resolve service names or external hosts — CoreDNS is down, blocked by NetworkPolicy, or the upstream resolver fails.
Failed to create pod sandbox: plugin type="calico" failed (add): ... (FailedCreatePodSandBox)
The kubelet couldn’t set up the pod’s network sandbox — almost always a CNI plugin problem or exhausted pod IPs.
spec.ports[0].nodePort: Invalid value: 80: provided port is not in the valid range. The range of valid ports is 30000-32767
A NodePort Service asked for a port outside the cluster’s NodePort range (default 30000–32767).
CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views
Background code updated a View directly; UI changes must happen on the main thread.
Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline."
URLSession couldn’t reach the network — the device is offline, the app’s cellular data is disabled, or the simulator lost network…
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.
ECS task stopped: CannotPullContainerError: pull image manifest has been retried ... / ref pull has been retried
The ECS task couldn’t pull its image — no network route to the registry, missing ECR permissions, or a wrong image tag.
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).
HttpRequestException: No connection could be made because the target machine actively refused it (localhost:5001)
Nothing is listening on the host/port the client called — the API isn’t running, uses another port, or the container/network addr…
Ingress returns "404 Not Found" / "default backend - 404" (ingress-nginx)
The ingress controller received the request but no Ingress rule matched the host/path, so it answered with its default backend.
ANR: Application Not Responding (Input dispatching timed out)
The main thread was blocked for about 5 seconds (input) or a broadcast/service took too long, so Android showed “App isn’t respon…
Two steps away (33)
MySQL ERROR 2006 (HY000): MySQL server has gone away
The connection to MySQL was closed — usually by a timeout or a packet larger than `max_allowed_packet`.
HTTP 408 Request Timeout
The server closed the connection because the client took too long to send the complete request.
HTTP 499 Client Closed Request (Nginx)
Nginx-specific code logged when the client disconnected before the server finished responding.
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.
net::ERR_NAME_NOT_RESOLVED (This site can't be reached — server IP address could not be found)
DNS couldn’t resolve the hostname in the browser.
cURL error 6: Could not resolve host: api.example.com
PHP cURL couldn’t resolve the hostname via DNS.
Kubernetes: Pod Evicted — The node was low on resource: memory / ephemeral-storage
The kubelet removed the pod because its node ran short of memory or disk.
Kubernetes node NotReady (Kubelet stopped posting node status)
The control plane hasn’t heard from a node’s kubelet, or the kubelet reports a problem — pods there stop being scheduled and are…
Service has no endpoints (no endpoints available for service / Endpoints: <none>)
The Service’s selector matches no ready pods, so traffic to it is refused or returns 503.
Error response from daemon: network X not found
The container or Compose project refers to a Docker network that doesn’t exist (any more).
Job for nginx.service failed because the control process exited with error code
systemd tried to start the service, but its start command failed. The real reason is in the service’s status/journal.
Failed to start x.service: Unit x.service not found
systemd has no unit with that name — the package isn’t installed, the name differs on this distro, or a new unit file wasn’t load…
AAPT: error: resource android:attr/lStar not found
A dependency (androidx.core 1.7+) uses an attribute from Android 12 (API 31), but your module compiles against an older compileSd…
AAPT: error: resource x (aka y) not found — Android resource linking failed
A layout, manifest or style references a resource (drawable, string, style, attribute) that doesn’t exist in the module or its de…
WindowManager$BadTokenException: Unable to add window -- token null is not valid; is your activity running?
A dialog or popup was shown with a context whose Activity is finishing/destroyed, or with the Application context.
App Transport Security has blocked a cleartext HTTP resource load
iOS blocked an `http://` request (or a weak-TLS HTTPS one) because App Transport Security requires secure connections.
Error: listen EADDRINUSE: address already in use :::3000
Another process is already listening on that port.
Docker: Bind for 0.0.0.0:80 failed: port is already allocated
Another container or host process already publishes that host port.
Cloudflare Error 1020: Access Denied
A Cloudflare firewall/WAF custom rule blocked the request — the visitor’s IP, country, user agent or request pattern matched a bl…
Kubernetes: ImagePullBackOff / ErrImagePull
The node can’t pull the container image — wrong name/tag, missing registry credentials, or registry unreachable.
npm ERR! code EROFS — EROFS: read-only file system
npm tried to write to a read-only location (read-only container filesystem, mounted volume, or system path).
denied: Your authorization token has expired. Reauthenticate and try again. (Amazon ECR)
Docker’s login to Amazon ECR has expired — ECR tokens last 12 hours, so pushes and pulls fail until you log in again.
docker compose: services.x Additional property y is not allowed / yaml: line N: mapping values are not allowed
The compose file is invalid YAML or uses a key Compose doesn’t recognise at that level (usually an indentation mistake).
docker-compose: command not found / 'compose' is not a docker command
Your system has only one of the two Compose flavours: the old docker-compose (v1) binary or the newer docker compose (v2) plugin.
service "web" depends on undefined service "db": invalid compose project
A service lists depends_on (or links/networks) for a service name that isn’t defined in the Compose file(s) being used.
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
System.IO.IOException: Failed to bind to address http://127.0.0.1:5000: address already in use
Kestrel can’t listen because another process (often a previous run of the same app) uses the port.
HttpRequestException: The SSL connection could not be established, see inner exception. (AuthenticationException: The remote certificate is invalid)
HttpClient couldn’t complete the TLS handshake — untrusted/self-signed certificate, name mismatch, expired certificate, or TLS ve…
HTTP 404 Not Found
The server can’t find anything at the requested URL.
Error from server: admission webhook "validate.nginx.ingress.kubernetes.io" denied the request
A validating admission webhook (ingress-nginx, Gatekeeper/OPA, Kyverno) inspected your object and rejected it; the reason follows…
HTTP 504 Gateway Timeout
A proxy or gateway waited too long for the upstream server to respond and gave up.
Cloudflare Error 524: A Timeout Occurred
Cloudflare connected to the origin, but the origin didn’t send an HTTP response within 100 seconds.
HTTP 304 Not Modified
The cached copy is still valid, so the server sends no body and the client reuses its cache.
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