@Franky > Thanks for your feedback. Our lighting plugin is still in its first public version and currently only supports a variety of functions for limited fixture types (movers, pars, bars, strobes, pin spots). Even if a fixture is listed in the database, it may not be supported by the lighting program, or have access to all of the features of that light (eg. prisms, gobos, zoom, pixel-mapping). Others may need a tweak to the database programming to get them working properly due to the manufacturer's DMX programming.
Your Indigo 6500 should work for the basics, provided you have assigned the correct number of channels for the fixture to match the selected profile and the DMX addresses are correct. If not, it could be a database issue and we can look into it, but please check your configuration first.