That is not application server problem. You just follow below process and overcome this unwanted error.
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Login Your Database Server.Then
#sqlplus sys as sysdba
Run Below command.
sql> alter system set sec_case_sensitive_logon=FALSE;
Then Restart your application server and start all service.
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Login Your Database Server.Then
#sqlplus sys as sysdba
Run Below command.
sql> alter system set sec_case_sensitive_logon=FALSE;
Then Restart your application server and start all service.
ENJOY