who can help, I am not a database administrator

first i download the latest Database App Development VM

from https://apex.oracle.com/en/learn/tutorials/

then, in the

sqlnet.ora (/u01/app/oracle/product/version/db_1/network/admin/) i set

SSL_VERSION=1.2 or 1.1 or 1.0 or 3.0

I try to send a mail and get the message

ORA-29019: The protocol version is incorrect.