feat: add troubleshooting guide for docker network errors

Signed-off-by: Nicolas Crocfer <[email protected]>

Author: ncrocfer

docs/troubleshooting.md

@@ -71,3 +71,36 @@ CSRF_TRUSTED_ORIGINS = [
 ```
 
 For more information, refer to the [Django documentation about `CSRF_TRUSTED_ORIGINS`](https://docs.djangoproject.com/en/5.1/ref/settings/#csrf-trusted-origins).
+
+
+## Docker build fails due to network issues
+
+During installation with `./install.sh start`, the Docker build may fail with messages like:
+
+```
+Connection timed out [IP: 151.101.194.132 80]
+E: Unable to locate package git
+```
+
+This means the container could not access the internet to fetch packages. This issue is related to your **host machine or Docker network configuration**, not to OpenCVE itself.
+
+You can work around the issue by forcing Docker to use the host network during the build. Edit your `docker-compose.yml` and add `network: host` under the `build` section of the service that fails, for example:
+
+```
+webserver:
+    env_file:
+      - .env
+    build:
+      context: ../web/
+      network: host
+      ...
+```
+
+Then run the installation again:
+
+```
+./install.sh start
+```
+
+!!!note
+    `network: host` only works on Linux. If you're on macOS or Windows, make sure your Docker has proper internet access and DNS resolution.