# Serverless connection errors: upgrade, do not debug DNS
## The errors
```
Failed to resolve 'controller.us-west-2.pinecone.io'
controller.us-west-2-aws.pinecone.io not found
Request failed to reach Pinecone while calling https://controller.us-west-2.pinecone.io/actions/whoami
```
## Cause
An outdated Pinecone client trying to reach a serverless index. Old clients speak the pod-era control-plane hostnames; serverless uses different routing. The docs are blunt: to connect to a serverless index you must use an updated client.
## Fix
```
pip install --upgrade pinecone
npm install @pinecone-database/pinecone@latest
```
Then retry the exact same code. If it still fails, check the network path (firewall, proxy) separately; but upgrade first, because DNS debugging an obsolete hostname is wasted work.
## Trap
Adding the controller hostname to /etc/hosts or working around TLS. The hostname is wrong because the client is old, not because DNS is broken.