Pimax 5K+ AMD RX6900 XT, no connection with Display Port

Hello, i got an Problem when i changed from RTX 3070 to AMD RX6900XT, With Nvidia all was fine but the Pimax wont connect to my RX6900XT, both Display Ports are testet, both work with an usual Monitor. But my Pimax VR Headset always asks für Connection to Display Port, Error 105000. AMD GPU Drivers are latest, Pitool Versions Testet are 1.01.263, 1.01.266 and 1.01.268.
Any Solution?
Thanks
Thomas