On the 27th of January (Wednesday), we were unable to accept new orders for GameStop (GME) and AMC, as our intermediary Interactive Brokers were unable to process them due to their increased volatility.
The unprecedented market activity in GameStop (GME) caused an extreme strain on the entire trade execution ecosystem worldwide and affected almost every trading platform. Subsequently, larger companies and brokers had to deposit additional collateral which resulted in halting the two stocks from new 'Buy' orders.
Further information regarding the two instruments can be found on our community here.