The supplier of our ERP system has provided us with a small program that uses an ODBC connection to connect to the system's database. The ODBC is setup as a system DSN using SQL server on a Windows 2003 R2 machine, connecting to a database running on MSSQL 2008 R2. The DSN connection test is successful using a defined SQL username and password (so no windows authentication).
However, when we start the application, an error log is generated stating the following error:
ERROR  [Microsoft][ODBC SQL Server Driver][SQL Server]Login failed for user ''.
When I checked with the supplier they told me that they are aware some ODBC connections don't work due to a windows authentication issue and they haven't been able to figure it out, and gave me an alternative way to connect. But because this forces me to store the username and password in plain text I'm reluctant to use this. So I did a bit more digging, and in the MSSQL error log I found the following message:
2014-02-07 10:18:11.95 Logon Error: 18456, Severity: 14, State: 58.
2014-02-07 10:18:11.95 Logon Login failed for user ''. Reason: An attempt to login using SQL authentication failed. Server is configured for Windows authentication only. [CLIENT: 192.168.x.xx]
We double checked the security settings are the server is definitely configured in mixed mode.
Does anyone have any idea why this error might be shown?