LEDE 17.01.1, pppoe connection issue

My device is Lenovo Y1, met pppoe connection issue. every time, after I reboot my device. always show me no internet connect. I login web console, checked pppoe-wan, had IP address, but I can not access internet, until I click 'connect' manually, then re-connect (ip address will be changed), issue gone. is there any method to fix it? thanks