Can't download other skins

I have recently purchased a second Raspberry pi 3 and have installed Rasplex. Everything seems to be working fine except I’m for some reason unable to select any other skins than the default skin OpenPHT 1.8.0. Not the dark version or the Aoen Nox skin shows up. Does anyone have any idea why this is? I’ve tried restarting the pi and disconnecting and reconnecting the wifi connection, but still only the default skin.

Thanks
Jonas

right now you cant use the download function of the skins, the https certificate of openpht.tv its expired

13:19:02 T:1963071376   ERROR: CCurlFile::FillBuffer - Failed: Peer certificate cannot be authenticated with given CA certificates(60)
13:19:02 T:1963071376   ERROR: CCurlFile::Open failed with code 0 for https://addons.openpht.tv/openpht-1.8/skin.aeon.nox.5/skin.aeon.nox.5-5.4.0.zip.md5
13:19:02 T:1963071376   ERROR: Open - failed to open source <https://addons.openpht.tv/openpht-1.8/skin.aeon.nox.5/skin.aeon.nox.5-5.4.0.zip.md5>
13:19:03 T:1766847456   ERROR: CCurlFile::Stat - Failed: Peer certificate cannot be authenticated with given CA certificates(60) for https://addons.openpht.tv/openpht-1.8/skin.aeon.nox.5/skin.aeon.nox.5-5.4.0.zip
13:19:03 T:1766847456   ERROR: CCurlFile::FillBuffer - Failed: Peer certificate cannot be authenticated with given CA certificates(60)
13:19:03 T:1766847456   ERROR: CCurlFile::Open failed with code 0 for https://addons.openpht.tv/openpht-1.8/skin.aeon.nox.5/skin.aeon.nox.5-5.4.0.zip
13:19:03 T:1766847456   ERROR: DeleteFile - cant delete file </storage/.plexht/addons/packages/skin.aeon.nox.5-5.4.0.zip>. trying lower case </storage/.plexht/addons/packages/skin.aeon.nox.5-5.4.0.zip>

Also, because of this the automatic updates arent working, so anyone updating from 1.7 to 1.8 must reflash the device