Do you get this message when you click E-Hentai Gallery links?
For example if you try to visit http://g.e-hentai.org/g/681006/5fe6a1b921/ and you don't have access to it like I do, you will get the error message.
Why do they do this?
It's because advertisers on E-Hentai galleries didn't like lolicon, shotacon, bestiality, incest etc (can't remember all the words) content on the site.
Originally thought to have been removed, such content is made available in a hidden site at http://exhentai.org which does not have ads.
If you want to visit the EX version of a E-Hentai Gallery, you can change the g.e-hentai.org to exhentai.org, like http://g.e-hentai.org/g/681006/5fe6a1b921/ to http://exhentai.org/g/681006/5fe6a1b921/.
Note you must have an E-Hentai account, and already have access to exhentai.org.