Ok sorry Armin i have to check back again.
During the process of get the website running a set of new problems emerged.
as i said, i had the old version of the Full Screen Slider installed, everything worked fine, except
once you entered the site through the domain adress mostlyviewedbycows.net it didn´t show the installed web font and just a substitute one. (only through paulbarsch.de/mostlyviewedbycows - where the wordpress is installed - it was visible)
So i refreshed the redirection, this caused the redirection to not work anymore, somehow.
i wrote the provider, they said the problem is not on their side ( Ihr Weiterleitungsziel enthält wahrscheinlich einen Befehl (header-redirect / relocation) der sich nicht mit unserer URL-Hiding-Weiterleitung verträgt.) and insted of an url-hiding redirection i should use the frame-redirection option.
it worked desktop, but mobile it caused total glitch.
i switched to open-redirection, now it shows the url where the wordpress is installed on (which i want to avoid)
A switch back to frame-redirection does not work anymore at all.
And since then some of the text in mobile is aligned left, although everything is set to be aligned center (in the text format and even if you set the text to aligned right directly in the text field). also after clearing the text formating, using a different format, deleting the row/slide and putting it up again,......
turning the phone, causes a black screen,.... or sometimes shows just a blue screen on arrival.
when i disable the full screen slider for phone, then the text is back to aligned center (which is the current state)
if the phone is held horizontal the text size is right if you turn the phone to vertical the text size changes
i guess this all has to do with the add-on, and is maybe related to the old version,
but this redirecting thing, i have no clue whats going on......and how to fix that.