The queue 'SYSTEM.MQEXPLORER.REPLY.MODEL' could not be opened for reason '2195'. (AMQ4402) | Open for temporary reply queue failed rc=2063

Ok you have done something with your queue manager , either you have changed some params or you have tried to kill it by using kill command or may be you have done something unknowingly and getting above error message. so here is how to fix this.

You are having problem with your user id which was registered with Queue manager. fix it.

setmqaut -m <QM Name> -t q -n SYSTEM.DEFAULT.MODEL.QUEUE -p <user id> +inq +browse +get +dsp

QM Name - Your queue manager name where you are trying to connect from MQ explorer or from RHFUTILC or RFHUTIL

User Id - user id which you are using to connect to Queue manager or basically user is where you are running your client ie. it may be your system user name.