Connection problems

SSLHandshakeException: Certificate Expired (Validity Check Failed)

What it looks like in the log

javax.net.ssl.SSLHandshakeException: (certificate_expired) PKIX path validation failed: java.security.cert.CertPathValidatorException: validity check

How to fix it

  1. Check your operating system's Date & Time settings, turn on 'Set time automatically', and click 'Sync now' to ensure your PC clock is not set in the future or past.
  2. If this happens in HMCL or another third-party launcher during downloads or update checks, open the launcher's Download settings and switch the download provider/mirror (for example, between Official and BMCLAPI).
  3. Test whether the outage is server-side by opening the launcher's website (such as docs.hmcl.net) in a web browser; if your browser also warns that the certificate expired, you can ignore update/help errors, launch installed instances normally, and wait for the maintainers to renew their certificate.
  4. Disable any HTTPS-filtering proxy, VPN, or antivirus 'Web Shield' temporarily, and update your Java runtime (Java 17 or 21) so your local truststore has current root certificates.
LoadersVanilla, Forge, Neoforge, Fabric, Quilt, Server
SeverityBreaks something
CategoryConnection problems

Check your own log

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