Wireless network connection interrupted when connecting an external monitor

Hello everybody,

i have recently bought a Dell XPS 13 and I have some troubles with the wireless network connection.

Every time I connect my external monitor via a hdmi to usb-c Adapter the wireless connection is interrupted or extremely slow.

the adapter is a usb-c to hdmi / sd card / USB adapter.

the Monitor shows a Resolution of 2560 x 1440 at 60 Hz.

When switching the resolution of the external monitor to a lower resolution with lower Hz the network is working again.

i have tested the network speed between the XPS13 and another PC in the network.

I would appreciate any help that helps to solve this problem.

Thanks

Phil