Cannot connect to PPPoE Clients by IP from pppoe pool

Hi all,
I have strange issue, cannot access my clients CPE by IP provided from pppoe pool,I can ping ,traceroute but no access to CPE GUI.
I am using RB1100AH v6.7 with 2WAN ,loadbalancing PCC and pppoe server on same router.
Please help,
Thank you in advance