PPPOE take long time to up

Hi all, Im using FG301E on firmware 6.0.4. 

The issue is when the device launch pppoe, it takes about 3 minutes to get the ip-address from the ISP , but when i use router Draytek or even Laptop to connect, it just cost few seconds to get an IP .

Here is my configuration  : 

edit "port1" set vdom "root" set mode pppoe set allowaccess https http set type physical set alias "WAN1" set role wan set snmp-index 3 set username "xxxxxx" set password xxxx set padt-retry-timeout 0 set mtu-override enable set mtu 1492

Please have a look and give me some advices . 

Thanks in advance.