Configuration property ...dfs.core.windows.net not found using JDBC with Azure Synapse external tabl

I'm using the JDBC driver to query an external table in Data Lake Gen2 in Azure Synapse and getting the error below, is there something I have configured wrong? I have tried with dedicated SQL pool and using both parquet and csv.

This is the stack;

com.microsoft.sqlserver.jdbc.SQLServerException: External file access failed due to internal error: 'Error occurred while accessing HDFS: Java exception raised on call to HdfsBridge_Connect. Java exception message:

Configuration property datalakegen......dfs.core.windows.net not found.'

at com.microsoft.sqlserver.jdbc.SQLServerException.makeFromDatabaseError(SQLServerException.java:265)

at com.microsoft.sqlserver.jdbc.SQLServerStatement.getNextResult(SQLServerStatement.java:1673)

at com.microsoft.sqlserver.jdbc.SQLServerStatement.doExecuteStatement(SQLServerStatement.java:907)

at com.microsoft.sqlserver.jdbc.SQLServerStatement$StmtExecCmd.doExecute(SQLServerStatement.java:802)

at com.microsoft.sqlserver.jdbc.TDSCommand.execute(IOBuffer.java:7627)

at com.microsoft.sqlserver.jdbc.SQLServerConnection.executeCommand(SQLServerConnection.java:3912)

at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeCommand(SQLServerStatement.java:268)

at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeStatement(SQLServerStatement.java:242)

at com.microsoft.sqlserver.jdbc.SQLServerStatement.executeQuery(SQLServerStatement.java:724)

Cheers

David