The artist is ClariS (https://twitter.com/claris_staff ), from Japan.
They once wanted to be cute and changed their birthday to their debut date. Got account suspended. They eventually got the account back after a few months, but since then, their account is shadow banned in the US and some other countries like EU.
If you check their page, you can see no followers or followings; you can "follow" them, but only find it gone after refreshing. And you obviously won't get any tweets in your timeline.
I've contacted Twitter support numerus times, not helpful. I tried to contact their staff too but they obviously don't speak English and didn't reply.