Guides
A useful place to start, with a route to the related result.
Guides 145–168 of 348
Troubleshooting guide
After moving email away from your web host, check the host's mail routing setting
On cPanel-style hosting the server can decide it is your mail server. Learn how local, backup and remote routing differ, and why website mail to your own domain can vanish after a move.
Troubleshooting guide
Read the bounce message first: what each part of an email failure tells you
A bounce message names the failing step. Learn how enhanced status codes such as 5.1.1, 5.1.2 and 5.7.x split address, domain and policy faults before you change any DNS.
Troubleshooting guide
Why forwarded email gets rejected or junked, and what to use instead of a forward
A forward resends mail from your server, which can break SPF, alignment and DKIM at the final receiver. See what each provider documents, and when an alias or shared mailbox is safer.
Troubleshooting guide
Moving Google Workspace mail to Microsoft 365: what happens to Gmail labels, and what you can leave out
Gmail labels are not folders, and one message can carry several. Decide what to leave out, run a pilot to see how labels arrive, and learn what Microsoft's migration does and does not document.
Troubleshooting guide
Moving a WordPress site: the files, the database and the web address stored inside it
A WordPress move copies two things and sometimes rewrites a third. Learn when the address must change, why a blind find-and-replace corrupts settings, and how to test before DNS.
Troubleshooting guide
WordPress hardening: what each common measure does, what it cannot do, and a safe order
WordPress's own hardening guide calls its measures risk reduction, not elimination. Learn what each does, which caveats apply, and an order that protects you from breaking the site.
Troubleshooting guide
Hacked WordPress site: restore a clean backup or clean in place, and what a restore cannot do
WordPress's own advice for a hacked site starts with documenting, resetting passwords and fresh files. Learn what checksum checks can and cannot prove and when to stop and take advice.
Troubleshooting guide
A browser test fails when the page is slow: wait for a condition instead of pausing for a fixed time
Read a Playwright timeout as a question about which condition was not met, use the waiting the tool already does, and stop lengthening pauses that still fail on a slow day.
Troubleshooting guide
Browser tests pass alone and collide when run together: give each test its own account and data
Separate what Playwright isolates in the browser from the server-side data that parallel workers still share, and use per-worker accounts and unique identifiers to stop tests interfering.
Troubleshooting guide
A browser test passes on your laptop and fails in CI: collect a trace before changing anything
Capture evidence from the failing CI run with Playwright's trace viewer, compare the environment differences that matter, and change one thing at a time instead of loosening the test.
Troubleshooting guide
Before refactoring an untested module, record what it does today with characterisation tests
Record the behaviour a module has now, without deciding whether it is right, and learn what a coverage figure does and does not tell you about the safety net you just built.
Troubleshooting guide
npm audit reports a vulnerable package you never chose: fix the parent before you reach for force
Read an npm audit report as a dependency path, apply fixes in order of safety, treat an override as a narrow temporary pin and keep a forced major update a decision rather than a default.
Troubleshooting guide
pip-audit reports a vulnerable Python package: separate the fixable findings from the pinned and the unfixed
Know what pip-audit examined, preview a fix before applying it, handle findings that have no fixed version and run the audit in an isolated environment.
Troubleshooting guide
A secret was committed to git: revoke it first, then decide whether to rewrite history
Order the response to a committed credential correctly: revoke, remove it from the code, decide on a history rewrite and its limits, and stop the next one with ignore rules and push-time scanning.
Troubleshooting guide
Error reports show minified code: make stack traces readable with source maps
Work out why an error tracker shows bundled, minified lines and check that the build, the upload and the deployed code agree, using a deliberate test error rather than waiting for a real one.
Troubleshooting guide
Check what your error reports contain before launch, and filter sensitive data at the source
Find out what an error event carries beyond a stack trace, choose where to scrub it, use a before-send hook and test the filter with invented secrets before real traffic arrives.
Troubleshooting guide
An error tracker that alerts on everything gets muted: tune grouping and alert rules
Understand how events are grouped into issues, why one fault becomes many issues, and how to build one alert rule that tells the right person about the right thing.
Troubleshooting guide
Follow one request through your logs: structured records and a request ID in Python
Turn free-text log lines into records a program can parse and attach a request identifier with filters and context variables so every line from one request can be found together.
Troubleshooting guide
One slow endpoint or page: measure the distribution before you change any code
Build a measurement two people would agree on, read percentiles instead of averages, separate lab from field figures and decide what a believable before and after comparison has to show.
Troubleshooting guide
What a useful written pull request review contains, and what it cannot tell you
Set the standard for a written review of a pull request: what to look at, how to write a finding someone can verify and why a review informs a merge decision without making it.
Troubleshooting guide
Your setup instructions have never been run on a clean machine: test the README before you hand it over
Find the hidden prerequisites in a README by following it, and only it, on a clean environment, and know who should try it and what to record.
Troubleshooting guide
Scanning one page is not an accessibility audit: how to scope an audit of a single flow
Separate what automated accessibility checks find from what needs a person, scope an audit by complete process rather than by page, and know which WCAG 2.2 criteria are new.
Troubleshooting guide
A pytest test passes alone but fails in the full run: look for shared state first
Find what one test leaves behind for the next one, from wide fixture scopes to shared files and environment changes, and prove the cause by changing the order instead of guessing.
Troubleshooting guide
A test fails only at certain times or on some machines: find the clock, the randomness or the environment
Trace a test that depends on the date, a random value or the machine it runs on, and control that input instead of waiting for the next failure.
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