X509: Use -help for summary OpenSSL

Question

So I'm just trying to create a self signed cert using SSL. I've got to very last part but it won't complete. Every stage up to this point completed successfully. The command I'm trying to run is:

openssl x509 -req -days 3650 -in smime_test_user.csr -CA ca.crt -CAKey ca.key -set_serial 1 -out smime_test_user.crt -addtrust emailProtection -addreject clientAuth -addreject serverAuth -trustout

However I just get the reponse;

X509: Use -help for summary.

Hope this all makes sense, can anyone point me in the right direction?

Thank you for your time