Problems with symbology on arcpy.mapping

I have a layer that I added on a mxd through arcpy. However, the symbologyTipe is comming as "OTHER" and I need it to take the symbology as a UNIQUE CLASS. I can't change it and I tryed the UpdateLayer, but nothing happens to my layer. I tryed both in my script and following it on ArcMap.

I also tryed "arcpy.ApplySymbologyFromLayer_management" but it didn't work either.

Does someone knows how to do this?

Thanks!