Time Machine Server Issues

I have a server running OS X Yosemite Server. I am trying to get the time machine service configured so all of my other macs can do time machine backups to my server. After I enable the service and select a newly formatted hard drive as the backup location, all seems to be going fine. My iMac connected via ethernet backs up successfully to the server. But, the two MacBook Pros connected via WiFi do not complete their time machine backups. Every time I try to do a backup from a Wifi Laptop, it fails and brings my whole network down. No clients can access server shares and no internet access. The only thing I can do to recover from this is to reset my router. This crashing happens every time a laptop attempts to back up. What could be causing this issue?