nginx LB for tomcat server

I have a nginx plus Load balancing server and 2 backend servers running apache tomcat. When I connect to nginx LB IP, it just keeps requesting to the backend servers repeatedly (web browser keep refreshing the page). Please see attachment file of nginx.conf


Please support me with this, I will provide more information if you need

Load balancer IP: 172.29.1.124 (RHEL 7.4) / nginx version: nginx/1.15.10 (nginx-plus-r18)
Backend servers:
- 10.29.81.103, 10.29.81.104 running apache tomcat (jaspersoft)

Thanks