digital ocean - VPN PPTP - CTRL: PTY read or GRE write failed -

digital ocean - VPN PPTP - CTRL: PTY read or GRE write failed -

i build vpn server on digitocean using script https://raw2.github.com/suyan/scripts/master/setup/pptp.sh

however cannot connect vpn server using either iphone or mac. here /var/log/syslog says:

oct 31 18:44:29 vpn pptpd[1422]: ctrl: client xx.xx.xx.xx command connection started oct 31 18:44:29 vpn pptpd[1422]: ctrl: starting phone call (launching pppd, opening gre) oct 31 18:44:29 vpn pppd[1423]: plugin /usr/lib/pptpd/pptpd-logwtmp.so loaded. oct 31 18:44:29 vpn pppd[1423]: pppd 2.4.5 started root, uid 0 oct 31 18:44:29 vpn pppd[1423]: using interface ppp0 oct 31 18:44:29 vpn pppd[1423]: connect: ppp0 <--> /dev/pts/1 oct 31 18:44:59 vpn pppd[1423]: lcp: timeout sending config-requests oct 31 18:44:59 vpn pppd[1423]: connection terminated. oct 31 18:44:59 vpn pppd[1423]: modem hangup oct 31 18:44:59 vpn pppd[1423]: exit. oct 31 18:44:59 vpn pptpd[1422]: gre: read(fd=6,buffer=b77c8480,len=8196) pty failed: status = -1 error = input/output error, caused unexpected termination of pppd, check alternative syntax , pppd logs oct 31 18:44:59 vpn pptpd[1422]: ctrl: pty read or gre write failed (pty,gre)=(6,7) oct 31 18:44:59 vpn pptpd[1422]: ctrl: reaping kid ppp[1423] oct 31 18:44:59 vpn pptpd[1422]: ctrl: client xx.xx.xx.xx command connection finished

can help?

check link : pptp connection error: gre: bad checksum pppd

http://forums.whirlpool.net.au/archive/1957524

may helpful

vpn digital-ocean pptp