502 error Beanstalk with load balancer and vpc, Metabase

hello everyone,

I am trying to deploy the metabase service to my prod env using this method here I have been able to do it multiple times without any failure on my tests env.

I am facing a problem during the deployment of the environment, the health check is failing and the instance is unreachable resulting to a 502 bad gateway Here are the Health status :

Process default has been unhealthy for 6 hours 27 minutes (Target.FailedHealthChecks).
Instance has not sent any data since launch.

The load balancer receive the requests but fail to forward it according to the monitoring page.

It is obviously a problem on my production environment since it's working on the others but I have no clue where the problem is, I think it is linked to my VPC.

I have a VPC on my envs with private and public subnet all linked to an internet gateways such as the illustration below.

I am not a network expert and I do not know where to start. I have check all the route tables and try to see a difference between prod and tests and did no find anything. Of course I have tried to rebuild the app from scratch resulting to the same result.

I hope someone could lead me in the right direction.

Thanks a lot and have a nice day.