during boot:
Configuring VLAN interfaces...em0: link state changed to DOWN
vlan0: changing name to 'em0_vlan20'
em0: link state changed to UP
em0_vlan20: link state changed to UP
done.
Configuring LAN interface... .em0: link state changed to DOWN
em0_vlan20: link state changed to DOWN
em0: link state changed to UP
em0_vlan20: link state changed to UP
em0: link state changed to DOWN
em0_vlan20: link state changed to DOWN
em0: link state changed to UP
em0_vlan20: link state changed to UP
em0: link state changed to DOWN
em0_vlan20: link state changed to DOWN
em0: link state changed to UP
em0_vlan20: link state changed to UP
em0: link state changed to DOWN
em0_vlan20: link state changed to DOWN
em0: link state changed to UP
em0_vlan20: link state changed to UP
em0: link state changed to DOWN
em0_vlan20: link state changed to DOWN
em0: link state changed to UP
em0_vlan20: link state changed to UP
done.
Configuring WAN interface...
Connected switch confirms this in the log.
How to troubleshoot?