ORA-12547: TNS: lost contact
ORA-12547: TNS: lost contact Today while working on 19c upgrades I faced below oracle-error ORA-12547 TNS: lost contact After checking few oracle metalink documents, I came to know that the issue can be due to multiple reasons like as few below. Wrong permission of the executing Oracle binaries. Oracle binaries not linked correctly with linux OS. Listener can be in hung state. I checked for above issues, but in my case everything was good and still I was getting the same error. So after few hit and trial I saw that when the forward slash is appended to the end of the ORACLE_HOME environment variable. The connection to the database is successful. In below screenshot we can see that there is no forward slash at the end of the ORACLE_HOME environment variable. And we get the error. While In below screenshot we can see that when forward slash is appended at the end of the ORACLE_HOME environment variabl...