@m1scha
I checked out MMM-Remote-Control and it is just a problem with string representations.
remote?action=NOTIFICATION¬ification=“SELECT_PAGE”&payload=0
sends the literal notification “SELECT_PAGE” including the quotes. A more correct request would be remote?action=NOTIFICATION¬ification=SELECT_PAGE&payload=Main
which would switch the the page called main.
However, in order to support other modules, pages are 1 indexed by notification so to switch to the first page, you would send remote?action=NOTIFICATION¬ification=SELECT_PAGE&payload=1
Strings that are numbers are handled correctly by MMM-Page-Selector.