QTcpServer does not disable the read notification when subclassed and the incomingConnection() function is reimplemented to create a different type of socket, for instance a QSslSocket. The reason for this is that the internal queue is not exposed to the QTcpServer class so it's not possible to add the new socket to the queue, and thus the check for maxConnections in QTcpServerPrivate::readNotification() will never make disable read notification for the socket engine.