ORA-12547: TNS:lost contact

ERROR:
ORA-12547: TNS:lost contact

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Correct permissions should be:
ls -l ${ORACLE_HOME}bin/oracle
-rwsr-s--x 1 oracle dba 409028888 Aug 27  2019 bin/oracle

But now:
ls -l ${ORACLE_HOME}bin/oracle
-rwxr-x--x 1 oracle dba 457057360 Mar 28 08:07 /software/oracle/19c/bin/oracle
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How to fix:
Per Oracle technote "Troubleshooting ORA-12547 TNS: Lost Contact (Doc ID 555565.1)"
Solution is to make sure file system for database home has setuid/suid set, database binary($RDBMS_HOME/bin/oracle) has correct ownership and permission
su - oracle
cd $ORACLE_HOME/bin/
chmod 6751 oracle