I notice you're looking for "Minecraft Unblocked 76" — this likely refers to trying to play a version of Minecraft on networks (like school or work) that restrict gaming sites, possibly via a site called "Unblocked 76" or similar.

"Unblocked 76" refers to a specific community of sites that host Flash, HTML5, and JavaScript versions of popular games. For Minecraft, this typically manifests in three ways:

is a genuine technical marvel. It is a real port of Minecraft 1.5.2 or 1.8.8 that runs in a browser.