A new plugin auto detects rate hackers and kicks them from the server. Your current rate settings are illegal and form a latency hack by using non numerical values. It is possible if you have an old steam account that a bad server changed your settings years ago before valve removed it.

To correct the problem please enter the following commands into console:
rate: 25000
cl_updaterate: 101
cl_cmdrate: 101

This should allow you to connect to the server again.