redirect not working (HTTPS)

Could someone lend me some advice as to why this redirect isn't working?

 

The original setup is:

 

The subdomain is sub.abc.com which has an A-record of x.x.x.135.

 

The domain we which I want to direct to redirect is , which has the same IP and a A-record of x.x.x.135 as well.

 

I changed the sub.abc.com A-record to point to our redirect VIP on the BIG-IP like we do for most redirects.

 

We have a redirect VIP that is working for many other sites.

 

Summary - I changed the A-record of sub.abc.com to point to the redirect VIP and put the following iRule in place:

 

if {[string tolower [HTTP::host]] equals "sub.abc.com"}{ HTTP::redirect ";

 

}

 

sub.abc.com doesn't resolve when I do this.