Is Brass working in standalone mode?
If yes, in Logic, go to the Logic > Preferences> AudioUnits Manager menu, and make sure to validate the AU plug-in for Brass.
Sometimes, Logic doesn't do this automatically and you have to do a manual scan of the plug-in.
If it's not working in stand-alone mode, make sure you have the latest LicenseControl Center from Syncrosoft at:
www.elicenser.netThen open the LCC to check the Brass License on your USB dongle.
Sean