Guitar Rig 6 not working stand-alone mode!

Calle

Set up:

• The mac is recognising the interface and it has been selected under Settings -> Sound on my Mac
• Audient EVO interface: this is working fine, the signal coming in from the guitar on channel one (where it needs to be...), and the signal is also showing in the USB return Mac 1+2 Main Master fader. I can hear the guitar in my headphones. I can play music from Spotify, YouTube and so on, Protools work like a dream. All good. (see screenshot)
• GT 6: I have selected the EVO interface under the "Audio" tab. The interface shows up with the correct in/outs, sample rate and so on (see screenshot)
• BUT: no input is showing in the GR 6 input meter, no sound is processed by any of the amps presets, and no signal is coming through to e.g the tuner. Dead as Dodo.
• However, it works as a plug-in on ProTools.....but not in stand-alone mode eg for practising....very annoying!
• For reference, I also use Amplitude 5 which is working fine.

What to do? Grateful for any help.