> ## Documentation Index
> Fetch the complete documentation index at: https://docs.domino.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Errors during model build : Failed to establish a new connection: [Errno -2] Name or service not known')': /simple/prometheus-client/

#### ***Version/Environment (if relevant):***

4.x, 5.x

## **Issue:**

When deploying a Model API the build is very slow and the build logs list repeating network related errors like:

```
Jan 23 2023 18:14:08 +0100 #13 4.807 WARNING: Retrying (Retry(total=9, connect=None, read=None, redirect=None, status=None)) after connection broken by 'NewConnectionError('<pip._vendor.urllib3.connection.HTTPSConnection object at 0x7f081026bd90>: Failed to establish a new connection: [Errno -2] Name or service not known')': /simple/prometheus-client/
```

The model eventually deploys, but the build process is slow.

## **Root Cause:**

Model API initialization code tries to install the python package prometheus-client 0.11.0 (among others), a client for metrics & monitoring tools. If your system is air-gapped or public/internet access is tightly controlled your system might not be able to fetch that python package from [https://pypi.org](https://pypi.org), resulting in the error above.

## **Resolution:**

Install prometheus-client in your project's Compute Environment via a dockerfile instruction:

**RUN pip install prometheus-client==0.11.0**

If this isn't possible another idea is to modify pip's config files to make it not retry and "fail fast", like:

```
pip config --quiet --user set global.retries 0
pip config --quiet --user set global.timeout 1
pip config --quiet --user set global.disable-pip-version-check True
```

## **Notes/Information:**

If the above isn't possible please reach out to Domino Technical Support referencing DOM #36045 and DOM #41738


## Related topics

- [Troubleshooting](/knowledge-base/troubleshooting-overview.md)
- [ERROR: Could not install packages due to an EnvironmentError: [Errno 13] Permission denied:](/knowledge-base/error-could-not-install-packages-due-to-an-environmenterror-errno-13-permission-denied.md)
- [Deploy Domino endpoints](/cloud/platform-capabilities/features/model-deployment/index.md)
- [Unable to deploy Model - [Errno 13] Permission denied: '/.cache'](/knowledge-base/unable-to-deploy-model-errno-13-permission-denied-cache.md)