[SOLVED] Error: HTTPS certs for webadmin

[xoft]

I've found the cause and made a pull request with a fix: https://github.com/cuberite/cuberite/pull/4036

In the meantime, you can use your certificates if you convert them from PEM to DER (but keep their filenames).
( openssl x509 -inform pem -in certificate.pem -outform der -out certificate.crt )