Can't Get ANY Reverb VST On Vocal Channel To Work (MacOS)

[Fred Cap]

Using Mac JamKazam client. For the life of me I cannot get a reverb VST to effect the JamKazam channel I'm using for vocals.  I have tried using the GarageBand Apple Reverbs, Tone Booster Reverb, Tal-4 and many others without success. I have JamKazam pointed to my VST folder where I keep them all for use with my DAW (Studio One).  they show up in the list. I can add VSTs to the channel but when I open a session and try to add in the effect,  I dont get any effect on the vocals. 

I've also tried using  iZotope Nectar 2 which is what I would really like to use for vocal if possible.

If you've had success with adding VST effects to a vocal channel using the Mac Jamkazam client please share how you got it to work.

Thanks
Fred