Easy installer fails with Samsung S8 - Only official released binaries are allowed to be flashed

Sorry, actually it is not the same problem than described by eelo-in-Oz.
I tried to flash /e/OS on my Samsung S8 with easyinstaller. From the screen (see picture below) i cannot boot into TWRP.


I tried like it is described in this post
But it boots into Android recovery and looks like this:

What am i doing wrong?