Mediaelement along with immersive-slider -- not working

[Νικόλαος Σ]

I have used in the past immersive-slider to create slideshows for recent topics of a phpbb. Some topics have videos so I thought it would be nice to have a player within the slide and I successfully used mediaelement. The problem is that all of a sudden mediaelement stopped working. You can check it here as an example http://agiooros.org . I tried to use inspect (from chrome) but cannot find any problem.

[Νικόλαος Σ]

My site recently got a SSL and mediaelement now behaves properly.