Hi, first usual suspects when one is being blocked/prevented from navigating onto a site can include, double check with your (internet service provider) ISP; whomever the company is that you rely upon to get online. Generally speaking, both in earlier times and still, tho nearly as common present day, so still, (a) company=ISP that is offering net access is the owner of their servers. Accordingly, again, as a general rule,
As the providers, operators and owners of the servers, they customize whatever settings and the parameters therein, as they like.
Other, out of the gate reasons one can be prevented, blocked, from visiting a site,
1 of the most common and still seen on a rare occasion (more so present day) may likely have something to do with the websites international laws versus some end users state, country location. Additional typical reasons, further, can be anything from a glitch? A tech error? To an oversight, say, if somewhere within the fine print there might be a proof of age needed, matter to any number of things that may also be easy to over look? To be altogether, unaware of readily. Depending on the type of website it is has the potential to cause such an issue. For example, age restrictions?
(thus, there might be some documentation somewhere within the pre-intro page
And mentioned in say, the fine print, so to speak. Also, the issue could have something to do with 1 or more unknown issues for the end users part e.g. unknown software issue(s) that say, may be running in the background and possibly causing the problem. Possible RESOLVES(?) Best place to start troubleshooting the mystery is definitively, to call your ISP (to include an affirmative suggestion to insist on speaking with someone in upper management (manager? Supervisor? Systems operator(s)?) and not say, first point of contact staff.