路由器出现问题~~

我的网吧做的是无盘,带着55台客户机,,用的是硬路由器,(TL--R4148)    最近这几天,在路由器的日志里面出现了以下提示，,导致我连接路由器失败,请问这是什么原因?





1  0000:系统启动成功.
2  0069:DHCPS: 1:0x00e04d65f6f3, NAK in request.
3  0076:DHCPS: 1:0x00e04d73f562, NAK in request.
4  0087:DHCPS: 1:0x00e04d65fa06, NAK in request.
5  0629:DHCPS: 1:0x00e04d65fa16, NAK in request.
6  1386:DHCPS: 1:0x00e04d65a5d1, NAK in request.