There are many triggers causing an order to end up in this column. They should all relate to a problem occurring when the order has been tried communicated to a third party system (integrations).
Either a prerequisite was not set for the order or a parameter has not been accepted etc. Different integrations have different triggers for turning on the “order needs attention” flag.
When the system turns on the “Order needs attention” flag for an order it will also write a explanation text as part of the order history.
Pleas refer the order history for each individual order to for an explanation for why the “Order needs attention” flag has been turned on.
When you've dealt with the problem and the order has been processed correctly, you can use this button to remove the "Order needs attention" flag: