Help needed redirrect https Exclude one Client

Hi, im new to haproxy with maybe someone can help me, I have a redirect to https for all my sites in the front end but i need to make an exception to one client in a particular site

I was trying this:

acl elearning -m sub -i

http-request redirect scheme https if !elearning !{ src xxx.xx.x.x }

use_backend elearningserver01_ipvANY if -m str -i

It doesn’t work when I try to access the site using http, I get error 503 “There is no server available to handle this request.”

What is your full config? What does the haproxy log say?