I have zyxel prestige 600 ru t1 v2

I recorded reconnection. its ok. and tested. its Ok too.

but using JD
after first file downloaded modem automatically reset itself.

but :

PWR/SYS light ON
10/100m light ON
DSL light ON
PPP light OFF (so there is no internet connection)

what must I do ?????????

do I need enable Upnp from modem setup page???

why is my post gone to 2.page now? its the last post at this subject...?????