Oracle 19c and "no valid ip address returned for the host"

Solution 1:

After a week of hard work...

I managed to install, two possible reasons for this error:

1. I installed from my ORACLE account, but by "SU ORACLE" I did not log in as ORALCE, because then all the environment settings are loaded

2. I used another (newer) version of the oracle package for automatic configuration (https://yum.oracle.com/repo/OracleLinux/OL7/latest/x86_64/getPackage/oracle-database-preinstall-19c-1.0-2.el7.x86_64.rpm)

3. It's possible that I had a different hostname set in the oracle scripts than on the server in /etc/hostname - very likely, due to the content of the error...