Whenever I try to access the manga Restaurant to Another World via Safari on my Mac, I get the error "Manga is currently unavailable" despite the fact that the majority of the other manga work fine. I also can read it on my iPad just fine, or on the website if it is linkable from the Coming Soon section.
So it appears to be just this link that doesn't work:
While these links work:
It seems the 2 other manga introduced at the same time have the same issue, though I have not looked much into those.