Error: ORA-24327: need explicit attach before authenticating a user (DBD ERROR: OCISessionBegin) (4299300)

When doing a "Test System" on a Oracle system the following error is received: 

[MM/DD/YYYY HH:MM:SS] Gathering the information necessary to perform a check of oracle...
[MM/DD/YYYY HH:MM:SS] Checking the Oracle Database Server oracle(192.168.80.31:1521)...
[MM/DD/YYYY HH:MM:SS] Error: ORA-24327: need explicit attach before authenticating a user (DBD ERROR: OCISessionBegin)
[MM/DD/YYYY HH:MM:SS] Unable to connect to oracle to perform the check. Verify the network address, port, and Functional Account settings for the system.
[MM/DD/YYYY HH:MM:SS] Processed the system check on oracle in 23.5820312 seconds

1. Incorrect port/SID or ServiceName specified on the Systems Management | Connection tab in TPAM.

Confirm with the DBA, that the port number/SID and ServiceName are correct according to the Oracle system setup. The default port for TPAM/Oracle is 1521. This can be validated by looking at the listener.ora file on the Oracle system.

Validate that TPAM can access the port specified. A telnet test can be performed from the /tpam interface. Select Management | Network Tools | TelnetTest, and enter the server's network address, and port, then click "Test"

2. The At Symbol (@) in functional accounts password

Check that the functional accounts password does not include the @ symbol in their password.