Post an XML version of your feed and I will help you... This usually happens when your feed is in wrong format.
It looks like the problem is with your server SSL, The feed is not valid see here http://validator.w3.org/feed/check.cgi?url=http://wow.gnetwork.eu/feed/atom/Hi Joseph, i do not understand this
i only have the Feed in this Formats is this not xml?
Like Wordpress Codex only Avaiable is (https://codex.wordpress.org/WordPress_Feeds)
The App do not like one of them =o