Can't start when using a mongod.conf file that has the sslPEMKeyFile value set and no value for sslOnNormalPorts or sslPEMKeyPassword.

On the primary:

Tue Nov 22 04:34:31 [conn3] replSet replSetInitiate admin command received from client
Tue Nov 22 04:34:31 [conn3] replSet replSetInitiate config object parses ok, 3 members specified
Tue Nov 22 04:34:31 [conn3] replSet warning example.com:27017 replied:

{ errmsg: "need to login", ok: 0.0 }

On one of the other members:

Tue Nov 22 04:34:31 [initandlisten] connection accepted from 1.1.3.4:54322 #4
Tue Nov 22 04:34:31 [conn4] authenticate:

{ authenticate: 1, nonce: "2d2d2d2dd2d2d", user: "__system", key: "1372387dbd372e7328398dbd" }

Tue Nov 22 04:34:31 [conn4] end connection 1.1.3.4:54322

Fixing the mongod.conf to not set any of the 3 SSL options resolved the issue.

It may be better to have the mongod config / command line validation create a more visible warning related to SSL settings