Networking :: Poptop On Centos 5 - Continual Decline In Customers?

I need to understand what is happening with my VPN , I manage the Firewall server that have install POPTOP ($Id: pptpd.conf,v 1.10) for VPN conecctions. Actually only 3 users are using the service, about 1 month ago, I have problems with connection and service that consistently falls, sometimes it can get 1 hour of connection and then falls,My Server is on Centos , Kernell 2.6.18-53.el5PAE

This is my File on /etc/pptpd.conf

Code:

option /etc/ppp/options.pptpd
logwtmp
localip 192.168.10.1
remoteip 192.168.10.230-250

This is my File on /etc/ppp/options.pptpd

Code:

name servername
name pptpd
auth
refuse-pap

[code]....