I am having an issue where my forms builder 11.1.2.2 cannot connect to a 12.2.0.1 database if the schema password is all lower case. I can connect if the password is either mixed case or all upper case.
The database is an Oracle Virtual Box database, so I do not know if that matters.
Because it is a "pluggable" database, I cannot change the SEC_CASE_SENSITIVE_LOGON to FALSE.
I have Oracle Instant Client 11.2.0.3 that can connect to the 12.2.0.1 database in all three cases.
I have Oracle Instant Client 10.1.0.5 which exhibits the same behavior as the 11.1.2.2 forms.