Soemtimes you need to check your cluster name on your RAC  instance. Here is the steps:

cd $ORA_CRS_HOME/bin
./cemutlo -h        <=== will list all the options
Usage: ./cemutlo.bin [-n] [-w]
-n prints the cluster name
-w prints the clusterware version in the following format:

./cemutlo -n
clustergp1    <=== cluster name, default cluster name is “crs”

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