unable to verify LEAF signature

[SBits2019]

I am getting this error, when trying to use TLS.

UNABLE_TO_VERIFY_LEAF_SIGNATURE

my tls config is as follows;

const tlsOpts = {
  rejectUnauthorized: true,
  key: fs.readFileSync('./srv/ldapcert/key.pem'),
  cert: fs.readFileSync('./srv/ldapcert/cert.pem'),
};

I am on CentOS. I am using the base cert and the private key. I have been provided the complete cert chain and root + intermediate certs in pem format. I don't know what I am doing wrong, do I need to install the root certs in my trusted store or provide it in the config?

It works if I set rejectUnauthorized to false.