centos 6.5 64bit 安装 pptpd 错误 619 怎么办（附日志）

第一次用centos安装vpn，参考网上多个教程
安装好后，连接错误619
上网找答案，试过：
rm /dev/ppp
mknod /dev/ppp c 108 0
注释掉 logwtmp
开放GRE

但是还是连接不上，希望高手帮我看看日志（/var/log/messages）

Aug 10 14:18:06 centos0810 pptpd[3228]: CTRL: Client 117.00.111.22 control connection started
Aug 10 14:18:06 centos0810 pptpd[3228]: CTRL: Starting call (launching pppd, opening GRE)
Aug 10 14:18:06 centos0810 pppd[3229]: pppd 2.4.5 started by root, uid 0
Aug 10 14:18:06 centos0810 pppd[3229]: Using interface ppp0
Aug 10 14:18:06 centos0810 pppd[3229]: Connect: ppp0 <--> /dev/pts/0
Aug 10 14:18:09 centos0810 pptpd[3228]: CTRL: Ignored a SET LINK INFO packet with real ACCMs!
Aug 10 14:18:36 centos0810 pppd[3229]: LCP: timeout sending Config-Requests
Aug 10 14:18:36 centos0810 pppd[3229]: Connection terminated.
Aug 10 14:18:36 centos0810 pppd[3229]: Modem hangup
Aug 10 14:18:36 centos0810 pppd[3229]: Exit.
Aug 10 14:18:36 centos0810 pptpd[3228]: GRE: read(fd=6,buffer=611860,len=8196) from PTY failed: status = -1 error = Input/output error, usually caused by unexpected termination of pppd, check option syntax and pppd logs
Aug 10 14:18:36 centos0810 pptpd[3228]: CTRL: PTY read or GRE write failed (pty,gre)=(6,7)
Aug 10 14:18:36 centos0810 pptpd[3228]: CTRL: Client 117.00.111.22 control connection finished