CASTS1020I ES is configured to discard unsolicited CICS TN3270 input Enterprise Server CICS terminal control is configured to discard all unsolicited discard all unsolicited TN3270 messages.
i.e. it will discard TN3270 messages that arrive while a transaction is active for the target terminal unless the transaction
has issued an explicit CICS RECEIVE after the first CICS terminal control command.