Pro Tools- Akai MPK261- Synthmaster one vst plugin won't record arpeggiator

[Kiefer121061]

I use all of the above software/hardware.
I cannot get the vst version of Synthmaster One to record an arpeggio from the keyboard (Akai mpk261) The record function works fine on the standalone app without pro tools running. I've tried a lot and have searched to no avail.
Anyone else with this problem?
Keith