Blockate was put under review by Roblox administrators on the 18th of September, 2019, however no reason or explanation was given. This is known as the September 18th shutdown.
Speculations and Theories
Many users suggested that Blockate was shut down for being a copy of Blocklr or for just being too similar to Roblox, but these claims were radical and not very credible.
Another theory is that Blockate's head developer, Fewkz, had broke Roblox terms of service and got Blockate shut down; However this theory was also not very credible.
The most credible and believable theory is that the player-base has caused the shutdown, with many users thinking they were funny by building "items" that were against Roblox ToS, or most likely, the use of Discord Links.
Luisupro99's Theory (aka the theory that made the one that edited this page):Numbers are allowed (That means that bypasses the chat fliter, since sometimes numbers are censored while in Blockate they are always allowed) or like above, the players made games, but these games where games that have copyrighted things (Like these pokemon games, don't ask why the reason of this)
According to Twitter, the Blockate team are trying to “Make The Game Playable Again”. This does mean that Blockate is going to have a comeback, what really made it not playable has not definition answer yet. We can only guess why it was gone. It is speculated to come back in October.