Owncloud /firefox & Https dosen't work in Mint 18.1 serena

Hi all,
I installed OC 9 Mint 18.1.
I created my certificate to access via https.
I made the port forwording door 80; and 443;
I disabled the "firewall"
The problem is this:
1) when I access via http: // localhost / ownclod all right;
2) if I access via https: // localhost / owncloud /
Firefox tells me "unable to connect .... etc etc"
It seems like I have not the Internet connection.
Has anyone had a similar problem?
Im really stuck.

Not sure, can you give more details about the error? Can you connect to your server or is there an issue with your certificate. Is Firefox just complaing about an invalid certificate for localhost? On a public server, you can use the tests of ssllabs.com to verify your configuration.