thanks Ibersystems for rapid assistance
this is a mangle where is the point which will help in solving the problem .
/ip firewall mangle> p
Flags: X - disabled, I - invalid, D - dynamic
0 chain=input action=mark-connection new-connection-mark=wan1 passthrough=yes
connection-state=new in-interface=pppoe-out1
1 I chain=input action=mark-connection new-connection-mark=wan2 passthrough=yes
connection-state=new in-interface=pppoe-out2
2 X chain=input action=mark-connection new-connection-mark=wan3 passthrough=yes
connection-state=new in-interface=pppoe-out3
3 chain=output action=mark-routing new-routing-mark=wan_1 passthrough=no
connection-mark=wan1
4 chain=output action=mark-routing new-routing-mark=wan_2 passthrough=no
connection-mark=wan2
5 X chain=output action=mark-routing new-routing-mark=wan_3 passthrough=no
connection-mark=wan3
6 chain=prerouting action=mark-connection new-connection-mark=wan1
passthrough=yes dst-address-type=!local in-interface=lan
per-connection-classifier=both-addresses-and-ports:3/0
7 chain=prerouting action=mark-connection new-connection-mark=wan2
passthrough=yes dst-address-type=!local in-interface=lan
per-connection-classifier=both-addresses-and-ports:3/1
8 X chain=prerouting action=mark-connection new-connection-mark=wan3
passthrough=yes dst-address-type=!local in-interface=lan
per-connection-classifier=both-addresses-and-ports:3/2
9 chain=prerouting action=mark-routing new-routing-mark=wan_1 passthrough=yes
in-interface=lan connection-mark=wan1
10 chain=prerouting action=mark-routing new-routing-mark=wan_2 passthrough=yes
in-interface=lan connection-mark=wan2
11 X chain=prerouting action=mark-routing new-routing-mark=wan_3 passthrough=yes
in-interface=lan connection-mark=wan3
I have to disabled pppoe2&pppoe3 until the end of the imbalance