Mouse and Keyboard won’t work with KVM

Hi Everybody,
I installed a Tripp-lite 8 port powered KVM and connected 5 servers to it. Intially everything was fine until I disconnected one of the servers to work on it. When I reconnected the server to the KVM the mouse and keyboard freeze at the login screen. I have connected the server to another 2 port unpowered KVM and it works fine, tried differenct ports and changed cables and nothing seems to work. I can remote into the server and everything seems to be running fine. Any ideas?