[ovirt-users] [Cannot edit VM. Maximum number of sockets exceeded.]

Hi, when a user is managing a "higher number" (couldn't find the exact number yet, roughly >10) of VMs in VM Portal and wants to edit a VM he gets a "[Cannot edit VM. Maximum number of sockets exceeded.]" error message in the browser, which I also see in engine.log. I couldn't find the reason for this. I'm using squid as a SPICE Proxy at cluster level. oVirt version is 4.2.7, can anybody help me? thx matthias