### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

What happened?

After upgrading from v1.87.0 to v1.88.1, the LiteLLM Admin UI stopped working when deployed behind an nginx reverse proxy. The browser is redirected to the internal Docker container IP instead of the public URL.

Downgrading back to v1.87.0 immediately fixes the issue. This is a confirmed regression.

Steps to reproduce:

1. Deploy LiteLLM v1.88.x behind nginx reverse proxy (Docker Compose, `num_workers=4`) 2. Set `PROXY_BASE_URL=https://your-public-domain.com` and `FORWARDED_ALLOW_IPS=*` in environment 3. Navigate to `https://your-public-domain.com/ui` 4. Browser is redirected to `http://<docker_container_ip>:4000/ui/login/` — inaccessible from outside the Docker network

Expected behavior:

Redirect should go to `https://your-public-domain.com/ui/login/` — same as in v1.87.0.

Environment:

- LiteLLM version: v1.88.1 (broken), v1.87.0 (works) - Deployment: Docker Compose, `num_workers=4` - Reverse proxy: nginx with `proxy_set_header Host $host`, `X-Forwarded-Proto`, `X-Forwarded-Host` — all correctly set - `PROXY_BASE_URL` and…