What this error means
XDM checks every HTTPS server’s certificate, the same way your browser does, to make sure you’re really talking to that site and the file can’t be swapped in transit. A TLS error means that check failed or the two sides couldn’t agree on encryption.
Common causes and fixes
- Your computer's date and time are wrong. Certificates are only valid between two dates. Turn on automatic date and time in your system settings.
- Antivirus HTTPS scanning. Some security suites intercept HTTPS traffic with their own certificate. Browsers trust it, but other apps may not. Add XDM to the product's exclusions, or turn off “HTTPS scanning” / “SSL inspection” for XDM.
- Corporate or school network. Managed networks often inspect HTTPS with a company certificate. Ask IT whether the certificate is installed system-wide.
- The site's certificate really is broken (expired, wrong host name, self-signed). Your browser shows a warning for it too. Contact the site owner.
About “Ignore certificate errors”
Settings → Network has an Ignore certificate errors option. It turns off certificate and host-name checks for all downloads.
Use it only temporarily, and only if you trust the network
With verification off, anyone between you and the server could read or replace the file you download, including installers and other programs. Prefer fixing the cause above, and switch the option back off as soon as the download finishes.