I have a Balance 20 and 2 wans the second wan shows no default gatway 
Under your WAN setting. Click icon “?” at Connection Method and click “here”, uncheck “Default Route from BGP”
Hope fix your issue.
2 Likes
The IP for WAN2 has been statically assigned and whoever did that did not enter a default gateway IP.
Go to Network > WAN click WAN 2 and add a static gateway. Then click save then apply.
1 Like