"Timeout waiting for PADO packets"

Modem (to be in full bridge)  ==> Asus router doing ppp authentication

Problem is the asus is showing the above error and cannot initialize the pppoe connection.
Strange thing is if I use another non openwrt modem in bridge to establish the session first then swap the modem putting the openwrt back in place the internet continues to work unless anything is switched off for an extended period.

Here is my config on the openwrt based modem, what should I change

config interface 'loopback'
    option ifname 'lo'
    option proto 'static'
    option ipaddr '127.0.0.1'
    option netmask '255.0.0.0'

config globals 'globals'
    option ula_prefix 'none'
    option default_ps '0'

config device 'wanptm0'
    option name 'wanptm0'
    option macaddr '10:13:31:xx:xx:xx'
    option ipv6 '0'

config interface 'wan'
    option macaddr '10:13:31:xx:xx:xx'
    option ifname 'ptm0'

config config 'config'
    option wan_mode 'bridge'

config interface 'lan'
    option type 'bridge'
    option proto 'static'
    option ipaddr '192.168.1.1'
    option netmask '255.255.255.0'
    option ip6assign '64'
    option force_link '0'
    option ipv6 '0'
    option pppoerelay 'ptm0'
    list ifname 'eth0'
    list ifname 'eth1'
    list ifname 'eth2'
    list ifname 'eth3'
    list ifname 'eth5'
    list ifname 'ptm0'

config switch 'bcmsw'
    option reset '1'
    option enable_vlan '0'
    option qosimppauseenable '0'
    option jumbo '0'