power/ground connection on I/O pad

xiaoyisimonguo

Ran through ICC from setup to routed and dfm filled
But somehow the power/ground connections on I/O pads is not there, please see the picture.
we could see the port on VSS_3 ground pad. The VSS bus is just right above. The VSS port/terminal is METAL2 through METAL4.
A simple METAL2 path with Via12 array on VSS bus would be sufficient. I thought the operation should be done in preroute stage.
My preroute  command in tcl is below:

preroute_instances -route_pins_on_layer METAL4 -nets {VDD VSS}  -primary_routing_layer pin -extend_for_multiple_connections -extension_gap 10.0

I don't know what did I miss here, and I am struggling with this for a long time. Please help

Desingman