OKAY SOLUTION
Before: check in your main router the attached devices: ROON ROCK should be listed and also your device.
(if you have a second router which is not in bridge (installed as accesspoint) you get conflicting IP adresses. }
SOLUTION
When ROON is connecting to a device, it checks if it is certified.
When you have old firmware of your device (which was my case) ROON doesn’t recognises and says: not certified.
–>So update your firmware of your device, the ROON will recognise the device.
The firmware of the PS AUDIO should be updated: see website and below
Be Aware: to update the firmware PSAUDIO you download it on a SD card with memory 2 gb-max 32gb
—> (this info is directly from PS Audio USA, it was the case for my PS Audio perfectwave from 2010).
After doing this it works and Roon can connect with PS AUDIO