vEthernet lead to no network connectivity

Hi,

i have the following configuration set up:  net1, net2 are teamed together switch-indipended mode. connectivity to the network is given.

If i create a Hyper-V-switch (External) with option "Allow management operating system to share this network adapter" set i lose all connectivity to the network. the newly created vEthernet-Adapter is not able to obtain a IP from the DHCP, doesn't work with a static one also.

Anyone has an ida how to fix this?

Thanks

Frank

P.S. on another server simular set-up works well