Error Message - Leaderboard

[Skugun]

When I play the campaign mode, in stage/map selection, when I press "Details" button, then "Leaderboard", it shows the following error message: "Unable to connect at this time. Please check your connection". How do I fix it?

My info:
DRM-Free version, not Steam.
Already created an account in-game.
OS Linux Kubuntu 14.04 x64

I also have a Multiplayer question, but I'll ask it in the MP section.

Cheers!

EDIT: The MP question, just in case http://community.skullsoftheshogun.com/viewtopic.php?f=4&t=208

[17-BIT Borut]

Sorry for the late response, but the leaderboards are only supported in the Steam version (we use their leaderboard tech).