new Roon Rock sees PS audio, cannot connect. Roon on PC in same network plays well

Roon Core Machine

Windows 11

Networking Gear & Setup Details

TP link AC1750

Connected Audio Devices

Number of Tracks in Library

Description of Issue

In ROON running on my PC PS audio is working fine.

Today I have installed Roon on a NUC (Roon Rock): it sees PS audio, but systems says certifcate is not

What is wrong? This (below) is the message when selecting PS audio when I use NUC with Roon:

Translation: there is no valid certificate

BUT: when I use my computer however Roon with PS Audio is working well.

Below a screenprint when I use Roon installed on my PC: no certificate, but PS Audio is working.