Different theme logged out on PC and smartphone...

I am developing a mobile Xerte. When playing it directly from the editor (with preview.php or play.php) it is showing the chosen theme nicely. It does not matter if I do that on my smartphone or pc. Logged in on any device shows the good theme.

It changes when I log out and play the URL of the developed Xerte module on my smartphone. The chosen theme is then replaced by the default Xerte theme (Xerte online toolkits). When I log in on my smartphone in the Xerte installation and play the Xerte mobile module, the right theme is shown. Logged out: back to the Xerte Online Toolkits theme. It overwrites all other themes

Even more strange is that when I log out of the Xerte installation on my PC and play the mobile Xerte, it works perfectly.

Any idea somebody?

Problem solved:) More or less.
I noticed that I produced the Xerte online module on a http site. I played it from the same site, but then from https. Apparently things will mess up.