Robinhood doesn’t buy and sell stocks, they just run an app. Downstream they have a relationship with Citadel, which does the actual trading. In theory it could

Robinhood doesn’t buy and sell stocks, they just run an app. Downstream they have a relationship with Citadel, which does the actual trading. In theory it could have been Citadel that decided to stop allowing these trades, but Citadel has announced that they haven’t done that.