Azure F5 deployed using marketplace is unable to ping backend server

Hello All,

I have deployed Azure F5 load balancer using Azure market place. I created a Self-IP and made it part of Internal VLAN with IP address as 10.10.10.24/28 and the backend server is also in Azure hosted in Ubuntu with IP address as 10.10.10.21/28. I am unable to ping the backend server from F5 and vice-versa.

Sanity checks :

1. The Self IP is attached to untagged interface
2. port lockdown status is allow all
3. the MAC address associated with port 1.1 is correct and is in reference to subnet 10.10.10.24
4. curl works locally on backend server : 10.10.10.21
5. Able to ping self IPs from respective device that is F5 and backend server

Parallely I have installed apache2 on backend server and I am able to curl on port 80 on 10.10.10.21 IP but the health monitor check fails from F5 self IP for Http traffic. there is no NSG associated to this subnet

Any idea what could be wrong ? why is ICMP and HTTP health check is failing. I am troubleshooting since past 4 hours but with no success