RT-AC68U dual WAN showing "cold-standby" and didn't fail over

I thought I set up my dual wan properly, but last night when the primary WAN went down, the router didn't fail over. On checking, I noticed it was reporting "cold-standby":

https://www.dropbox.com/s/0h7casz1co1ic38/Screenshot 2018-12-27 10.15.54.png?dl=0

Here are the dual-wan settings:...

RT-AC68U dual WAN showing "cold-standby" and didn't fail over