I think the order of rules is wrong. I have been away for a few years so I am a but rusty but the more specific rules need to be at the top. You have the general rules on top so the other rules wont get used.
I have 2 WAN running and a mailserver. users need to access the mailserver through the WAN using http or https://mail.domain.com/ mail.domain.com translates to one of the real IP addresses I get from one of the ISPs.
if that ISP is down I would like the users to automatically get through to the other ISP.