Error: No usable certificates

(Error code 0216eb)

Possible sources

This error originated from one of the following locations within the iPXE source code:

crypto/x509.c (line 1947)

General advice

Try using the latest version of iPXE. Your problem may have already been fixed.
Try building iPXE with the debug option DEBUG=x509
You can contact the iPXE developers and other iPXE users.
Refresh this page after 24 hours. This page is actively monitored, and further information may be added soon.

Additional notes

(Please edit this page to include any of your own useful hints and tips for fixing this error.)

Add DEBUG=tls,x509:3,certstore,privkey to make line for relevant run-time debug info.

If you want to trust multiple root certificates, use one certificate per file and specify all files separated with comma as described in the commit that introduced the feature.

Checklist

Time: Check that your BIOS time is correct. I encountered this error right after resetting the CMOS. If the BIOS date is before the cert issue date, you should get this error. Use show unixtime:int32 to see computers time in seconds and compare that to current time.
Chain: Ensure the certificate is valid in the chain that iPXE trusts.