>From error message it feels like that private key is password protected. It is possible that while exporting the key some passphrase was set. If that is the case you need to remove the password protection of private key using openssl.
> Dec 6 21:15:36 portus postfix/smtpd[18839]: warning: cannot get RSA private > key from file "/etc/ssl/private/tlsprivate.key": disabling TLS support > > Dec 6 21:15:36 portus postfix/smtpd[18839]: warning: TLS library problem: > error:0906406D:PEM routines:PEM_def_callback:problems getting > password:pem_lib.c:110: > > Dec 6 21:15:36 portus postfix/smtpd[18839]: warning: TLS library problem: > error:0906A068:PEM routines:PEM_do_header:bad password read:pem_lib.c:457: > > Dec 6 21:15:36 portus postfix/smtpd[18839]: warning: TLS library problem: > error:140B0009:SSL routines:SSL_CTX_use_PrivateKey_file:PEM > lib:ssl_rsa.c:649:
