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Short guides, tested and sourced.

On certificates, domains and charts. Command output comes from our own runs, and every date links to its source.

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  1. Site still shows the old SSL certificate Certificates
  2. Send email to a Slack or Teams channel Certificates
  3. TLS client auth EKU removal: what breaks Certificates
  4. Let’s Encrypt expiry emails ended: what now Certificates
  5. Fix “CAA record prevents issuance” Certificates

Certificates

19 guides

Keep TLS certificates renewed, served and trusted, and hear about it when a renewal fails.

The tool for it: Expiry Watch

  1. 47-day SSL certificates: timeline and prep 9 min

    Public TLS certificates last at most 200 days since March 2026, 100 from March 2027 and 47 from March 2029. The sourced schedule, and how to prepare.

  2. Let’s Encrypt expiry emails ended: what now 7 min
  3. Certbot renew failed: what the error means 13 min
  4. ERR_CERT_COMMON_NAME_INVALID on your site 6 min
  5. ERR_CERT_DATE_INVALID: what it means 4 min
  6. Check SSL expiry: openssl, curl, browser 19 min
  7. Fix “unable to get local issuer certificate” 21 min
  8. What is lencr.org, and is it malware? 8 min
All 19 guides
  1. Site still shows the old SSL certificate 8 min
  2. Let’s Encrypt 64-day certificates: what to do 10 min
  3. Is Certbot auto-renewal working? 7 min
  4. Let’s Encrypt certificates for IP addresses 4 min
  5. nginx “ssl_stapling” ignored, no OCSP URL 4 min
  6. DNS-PERSIST-01: what it is, who supports it 5 min
  7. Send email to a Slack or Teams channel 6 min
  8. Let’s Encrypt YE1 and YR1 chain errors 12 min
  9. TLS client auth EKU removal: what breaks 9 min
  10. Fix “CAA record prevents issuance” 9 min
  11. Let’s Encrypt YE1 and YR1 certificates 10 min

Domains

9 guides

Know when a domain registration ends, what its statuses mean, which renewal emails to trust, and how to keep its mail records valid.

The tool for it: Domain expiration checker

  1. What happens when a domain expires 7 min

    An expired .com gets a grace period at the registrar, 30 days of redemption with a restore fee, then 5 days pending delete. The timeline, day by day.

  2. Domain status codes: what each one means 6 min
  3. How long does a domain transfer take? 7 min
  4. Who is my domain registrar and DNS host? 4 min
  5. How long do DNS changes take? 5 min
  6. RDAP vs WHOIS: how to look up a domain 9 min
  7. Is this domain expiration email a scam? 7 min
  8. Email stopped after changing nameservers 7 min
All 9 guides
  1. Can you have multiple SPF records? 5 min

Charts

5 guides

Get a chart into email, Slack, a README or a PDF, where JavaScript can’t run.

The tool for it: Chart Link

  1. Charts in email that actually render 7 min

    Why JavaScript charts never render in email, and how to send ones that do: PNGs sized for retina screens, dark mode, alt text, Gmail and Outlook quirks.

  2. Send charts to Slack: n8n, Zapier and Make 7 min
  3. Chart.js to PNG: browser and server export 6 min
  4. Charts in a GitHub README: images or Mermaid 6 min
  5. Charts in PDFs: vector SVG or 300 DPI PNG 7 min

33 guides, last updated . Missing one? Tell us what to write next.