Docker nginx-proxy : can't access gitlab from jenkins with domain name

I am currently developping a toolchain for my company in which I've used Docker to set Gitlab and Jenkins.

I use the jwilder/nginx-proxy to access to them with a domain name from the outside.

My problem is that when I try to configure Jenkins to have access to my Gitlab, I am getting a time-out error. It seems like the container can't interact between them by using the domain name.

I have found this question that had the same problem as me, unfortunately, his solution didn't resolve my problem.

Do you have any idea how I could make Jenkins get acces to Gitlab by using the domain name ?

Edit :

Here is my docker-compose file

version: '3'
services:
    nginx:
            container_name: nginx
            restart: always
            image: jwilder/nginx-proxy:latest
            ports:
                    - 80:80
                    - 443:443
            volumes:
                    - conf:/etc/nginx/conf.d
                    - vhost:/etc/nginx/vhost.d
                    - html:/usr/share/nginx/html
                    - /home/nginx/certs:/etc/nginx/certs:ro
                    - /var/run/docker.sock:/tmp/docker.sock
            labels:
                    - "com.github.jrcs.letsencrypt_nginx_proxy_companion.nginx_proxy=true"

    letsencrypt:
            container_name: letsencrypt
            restart: always
            image: jrcs/letsencrypt-nginx-proxy-companion:latest
            depends_on:
                    - nginx
            volumes:
                    - conf:/etc/nginx/conf.d
                    - vhost:/etc/nginx/vhost.d
                    - html:/usr/share/nginx/html
                    - /home/nginx/certs:/etc/nginx/certs:rw
                    - /var/run/docker.sock:/var/run/docker.sock:ro
            environment:
                    - NGINX_DOCKER_GEN_CONTAINER=nginx

    gitlab:
            container_name: gitlab
            restart: always
            image: gitlab/gitlab-ce:latest
            hostname: gitlab
            volumes:
                    - /home/gitlab/config:/etc/gitlab
                    - /home/gitlab/logs:/var/logs/gitlab
                    - /home/gitlab/data:/var/opt/gitlab
            environment:
                    - VIRTUAL_HOST=gitlab.domain.biz
                      #- VIRTUAL_PORT=443
                      #- VIRTUAL_PROTO=https
                    - LETSENCRYPT_HOST=gitlab.domain.biz
                    - [email protected]

    jenkins:
            container_name: jenkins
            restart: always
            image: jenkins:alpine
            volumes:
                    - /home/jenkins/jenkins_home:/var/jenkins_home:z
            environment:
                    - VIRTUAL_HOST=jenkins.domain.biz
                    - VIRTUAL_PORT=8080
                    - LETSENCRYPT_HOST=jenkins.domain.biz
                    - [email protected]
volumes:
    conf:
    vhost:
    html:

networks:
    default:
            external:
                    name: toolchain

Edit 2:

Message d'erreur du nginx-proxy :

nginx | nginx.1 | 2017/07/12 12:45:33 [error] 79#79: *356 upstream timed out (110: Connection timed out) while reading response header from upstream, client: xxx.xxx.xxx.xxx, server: jenkins.domai1n.biz, request: "GET /descriptorByName/github-plugin-configuration/checkHookUrl?value=https%3A%2F%2Fjenkins.domain.biz%2Fgithub-webhook%2F HTTP/2.0", upstream: "http://172.18.0.7:8080/descriptorByName/github-plugin-configuration/checkHookUrl?value=https%3A%2F%2Fjenkins.domain.biz%2Fgithub-webhook%2F", host: "jenkins.domain.biz", referrer: "https://jenkins.domain.biz/configure"

Message d'erreur dans Jenkins : Image of the error in Jenkins