can you telnet from the primary hub to the new sql server instance on IP and port for the sql server?
IE telnet 192.168.1.1 1433 as an example?
can you create and ODBC connection from the primary to the sql server using same username and password as the data_engine?
have you reentered the database information using IP address rather than DNS name in the data engine and restarted?
If none of the above helps I would suggest opening a support case.
you can also set the data_engine loglevel to 3 and logsize to 35000 and restart and check the logs for clues.