Errors setting up project JDBC connection

I'm having some problems trying to set up a connection to a MS SQL database.

I registered a database at project level using driver com.microsoft.sqlserver.jdbc.SQLServerDriver and successfully tested the connection.

Testing the connection from Configuration Connection in a new JDBC connection fails with a pop-up message containing: com.microsoft.sqlserver.jdbc.SQLServerException: Login failed for user 'x'.ClientConnectionId:aae75905-259a-45cf-a62a-7df67cddd431. As of this morning, in a new JDBC request the same database connection is listed twice in the Configuration Connection drop-down for some unknown reason.

An error also appears in the Ready! API log The JDBC driver [com.microsoft.sqlserver.jdbc.SQLServerDriver] is already registered. when testing the connection (successful or unsuccessful) from the project database level or JDBC request step level.

If I select <None> from the Configuration Connection drop-down and replace the PASS_VALUE with the actual password in the connection string then the connection tests successfully and I can view the tables in the database, but I don't really want to be doing this for a number of reasons. The Ready! API log still reports the same error as noted above though, but it doesn't seem to affect the functionality of the step.

Edit:

Since writing this a moment ago, I have noticed something else odd: I set up a new JDBC connection at project level and selected the same driver (com.microsoft.sqlserver.jdbc.SQLServerDriver), I successfully tested the connection, then visited the JDBC step to try this new connection. When I select this new connection the driver selected is weblogic.jdbc.mssqlserver4.Driver and as this is greyed out I have no control over this selection.

Any help appreciated,

Thanks