Server key does not appear to be valid [SOLVED]
From OpenSSL 1.0 change log:
Make PKCS#8 the default write format for private keys, replacing the traditional format. This form is standardised, more secure and doesn't include an implicit MD5 dependency. [Steve Henson]
However, the pfSense 1.2.3 needs the private key file in the previous, traditional format.
openssl rsa -in server.key -out server.key