# Why does my load balancer respond with an HTTP 503 error?

DigitalOcean Load Balancers return an HTTP 503 error when there are either no target Droplets [assigned to the load balancer](https://docs.digitalocean.com/products/networking/load-balancers/how-to/manage/index.html.md#nodes), or all of the target Droplets are unhealthy.

If all of your target Droplets are correctly assigned to the load balancer, check the following things to see if there is a problem:

- Make sure your [Cloud Firewall rules](https://docs.digitalocean.com/products/networking/firewalls/how-to/configure-rules/index.html.md) allow the target Droplet to accept traffic from the load balancer.
- Ensure that [private networking is enabled](https://docs.digitalocean.com/products/networking/load-balancers/how-to/manage/index.html.md#droplet-connectivity) on the Droplet and that the Droplet is in the [same VPC network as the load balancer](https://docs.digitalocean.com/products/networking/vpc/how-to/migrate-resources/index.html.md#migrate-droplets-into-a-vpc-network). If private networking is not enabled, you can [enable it](https://docs.digitalocean.com/products/networking/vpc/how-to/enable/index.html.md) and [migrate the Droplet](https://docs.digitalocean.com/products/networking/vpc/how-to/migrate-resources/index.html.md) into the target VPC network.
- Ensure the application on your target Droplets is running and listening on the VPC private IP.
- If you have [enabled PROXY protocol](https://docs.digitalocean.com/products/networking/load-balancers/how-to/manage/index.html.md#settings) on the load balancer, check that the application on the target Droplets is configured to expect PROXY protocol.
- Ensure your [load balancer’s health check settings](https://docs.digitalocean.com/products/networking/load-balancers/how-to/manage/index.html.md#health-checks) match your application.

## Related Topics

[How to Troubleshoot Load Balancer Health Check Issues](https://docs.digitalocean.com/support/how-to-troubleshoot-load-balancer-health-check-issues/index.html.md): Health checks often fail due to firewalls or misconfigured backend server software.

[Why do my load balancer's Kubernetes node(s) have the No Traffic status?](https://docs.digitalocean.com/support/why-do-my-load-balancers-kubernetes-nodes-have-the-no-traffic-status/index.html.md): Kubernetes service ’externaltrafficpolicy’ field controls how nodes respond to health checks.

[Why did all of my backend Droplets become unhealthy when I enabled PROXY protocol on my load balancer?](https://docs.digitalocean.com/support/why-did-all-of-my-backend-droplets-become-unhealthy-when-i-enabled-proxy-protocol-on-my-load-balancer/index.html.md): Enable PROXY protocol support on your Droplets.