My Final Post in 2023, weird issue was faced where a database system after Linux operating system reboot startups in a defect way. when you attempt to connect through Bequeath Protocol:

ERROR:
ORA-12547: TNS:lost contact

After investigation….The Solution:

cat /etc/oratab

current entry was the following:

ORCLCDB:/opt/oracle/product/19c/dbhome_1/:Y

changed it to:

ORCLCDB:/opt/oracle/product/19c/dbhome_1:Y

the extra ‘/‘ was causing the problem !

Typo’s can cause serious problems…it took some time to figure out the problem.