Cisco VOIP phone 7961 and side car model 7914

My receptionist is having issues with the Cisco 7914 side car all of the lights on the side car will go red and then the phone will reboot.  This has been happening to other users who use a side car.  Would this be an issue with the Phone, Side car or is the phone losing connection?  We are using POE, so computers are connected through the phone.  I have asked the question when the phone reboots do you they notice if their machine disconnects from the network.  No one has noticed this happening.