"Give up establishing PPP/LCP in REQSENT" on Yamaha RTX

Yamaha RTX is set up to receive PPTP connection, but client could not connect, like below:

2010/06/02 19:18:20: TUNNEL[14] PPTP connection is established: 220.100.223.36
2010/06/02 19:18:20: PP[ANONYMOUS01] PPTP Connect
2010/06/02 19:18:21: PP[ANONYMOUS01] SEND LCP ConfReq in STARTING
2010/06/02 19:18:21: ff 03 c0 21 01 01 00 13 01 04 07 00 03 05 c2 23
2010/06/02 19:18:21: 80 05 06 00 40 18 58
010/06/02 19:18:24: PP[ANONYMOUS01] SEND LCP ConfReq in REQSENT
2010/06/02 19:18:24: ff 03 c0 21 01 01 00 13 01 04 07 00 03 05 c2 23
2010/06/02 19:18:24: 80 05 06 00 40 18 58
2010/06/02 19:18:27: PP[ANONYMOUS01] SEND LCP ConfReq in REQSENT
2010/06/02 19:18:27: ff 03 c0 21 01 01 00 13 01 04 07 00 03 05 c2 23
2010/06/02 19:18:27: 80 05 06 00 40 18 58
...

2010/06/02 19:18:51: PP[ANONYMOUS01] Give up establishing PPP/LCP in REQSENT
2010/06/02 19:18:51: PP[ANONYMOUS01] PPTP Disconnecting, cause [PPP: LCP Timeou
t]
2010/06/02 19:18:51: TUNNEL[14] PPTP connection is closed: xxx.xxx.xxx.xxx

Adding "pppoe auto connect on" to "pp select anonymous" part solved this issue.

Some references
PPTP commands
http://www.rtpro.yamaha.co.jp/RT/docs/pptp/pptp-command.html
Setting samples
http://www.rtpro.yamaha.co.jp/RT/docs/example/pptp/pptp_example1.html
http://tomo.no-ip.com/goodstream/vpn/pptp/rtx1000/rtx1000.html