I have a working C# application running on my computer. I have given it to a colleague and he gets the dreaded ORA-12154 ERROR. After much searching and trying, we are at a loss at what to try next.
C# makes a connection like
using (var connection = new OracleConnection(ConnectionString))
"Data Source=MY_TNS_ENTRY;USER ID=usernm;Password=passwd"
I assume that it is using a different TNS names file and that in that one the
MY_TNS_ENTRY does not exist. Check out this question to see how to check which file it is using.