A user station for a serial bus system and a method for error signaling for a message received in a serial bus system are provided. The user station includes a communication control unit for creating a message to be transmitted serially to at least one further user station of the bus system, or for reading a message, received serially from at least one further user station, and a transceiver device for transmitting the created message on a bus line or for receiving a message from the bus line, the communication control unit and/or the transceiver device provide an ACK time window for an ACK signal and/or a NACK time window for a NACK signal in the message to be transmitted for a signaling of whether or not at least one further user station has identified an error in the transmitted message.