ORA-12638: Credential retrieval Failed

当它尝试连接到我们的一个Oracle数据库时出现错误消息。但是，我可以从sqlPlus和Toad连接好。我已经Googled，每个人似乎都说修改他们的sqlnet.ora文件

sqlNET.AUTHENTICATION_SERVICES=(NONE)

做了诀窍我还没有找到有替代方案的人。这是我的连接字符串的样子：

"PROVIDER=OraOLEDB.Oracle;DATA SOURCE=(DESCRIPTION = " & _
"(ADDRESS = (PROTOCOL = TCP)(HOST = server1)
(PORT = 1521))" & _
"(ADDRESS = (PROTOCOL = TCP)(HOST = server2)
(PORT = 1521))" & _
"(LOAD_BALANCE = yes) " & _
"(CONNECT_DATA = " & _
"(SERVER = DEDICATED) " & _
"(SERVICE_NAME = database_name_here) " & _
") " & _
"); " & _
"User Id=username_here;Password=password_here;"

对于我的VB代码，这很简单。

Private oracleDatabaseConnection As ADODB.Connection

Set oracleDatabaseConnection = New ADODB.Connection
oracleDatabaseConnection.Open oracleConnectionString

任何人都有什么想法？

谢谢。