If you open up the tools menu in your VST Host, (If you only use one VST then it becomes its own Host) you will find a menu item relating to midi and/or input, if you open this up you will find all the midi connections that are available on your computer, make sure only the one that relates to OMB is selected. (If you have others selected then the VST Host will receive information from those as well)
As a general rule of thumb, (For most use) set OMB to receive only information from your controller, then set your VST Host to only receive information from OMB.
Hope this helps.
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