MariaDB uses HAProxy IP instead of the WebServer IP

I have a HA Setup that goes like this:enter image description here

I made a user for the web server:

grant all on user_db.* to 'db_user'@'' identified by 'password'; 

But when I try to access it via this command: Haproxy runs on 3306

mysql -u db_user -p -h --port=3306 

I get:

Access denied for user db_user@ or 

Why does it use my HAProxy IPs? Is there any way to make it use my Web Server IP instead, for security reasons. Or is there any way to prevent my HAProxy servers from receiving data from a different IP? Example: allow only then block the others.