Error Autopsy
504 Gateway Timeout While Your Application Was Still Working
The proxy gave up at sixty seconds and returned a 504. The application finished at seventy four and wrote the result to nobody. Both were correct.
Error Autopsy
ETIMEDOUT, ECONNREFUSED, EHOSTUNREACH: Three Diagnoses
Three socket errors that read as 'the network is broken' are in fact three different answers to three different questions.
Error Autopsy
Connection Reset By Peer at Exactly Sixty Seconds, Every Time
Every failure logged at the same number of seconds of idle time. That regularity is the diagnosis: a load balancer idle timeout killing connections your…
Error Autopsy
EPIPE Broken Pipe on a Write That Was Perfectly Legal
Your code did nothing wrong and still the process crashed with EPIPE. The other end closed the socket first, and your runtime turned an ordinary network…
Error Autopsy
SSL wrong version number: the Port That Was Never 443
This error almost never means your certificate is broken. It means one side is speaking TLS and the other is answering in plaintext, and the mismatch shows…
Security
JWT Expired: When the Token Is Fine and the Clock Is Not
Tokens rejected as expired seconds after issue, or accepted long after they should have died. Both are the same bug seen from opposite ends.
Networking
You Fixed CORS and the Browser Kept Failing for Ten Minutes
Access-Control-Max-Age caches the preflight decision, including the one that said no. Here is why your fix looked like it did not work.
MicroVMs
The CORS Header Is Present Twice and That Is Why It Fails
You added the header at the proxy, your framework was already sending it, and the browser now rejects both. Duplicates are invalid, not additive.
MicroVMs
413 Request Entity Too Large When You Already Raised the Limit
You raised the body size limit and the upload still fails. There are almost always two limits, and the one you changed is rarely the one rejecting you.
Networking
TLS Handshake Failures: the Error the Server Actually Sent
handshake failure, protocol version, unknown ca and bad certificate all mean different things. Here is how to get the real reason out of a connection that…
MicroVMs
The Domain Resolved Everywhere Except Where I Was Sitting
A CNAME that dig confirmed, a browser that refused, and a certificate stuck on pending. Three separate caches pretending to be one problem.
DevOps
Your systemd Service Will Not Start and the Logs Say Nothing
status=203/EXEC, status=217/USER, and the other exit codes that mean something specific. Here is how to read them and what each one actually points at.