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

# How do I deal with network issues?

This page helps you resolve SSL and network errors that prevent Weights & Biases from syncing your training data, so you can keep experiments running even on unreliable or restricted networks.

If you encounter SSL or network errors, such as `wandb: Network error (ConnectionError), entering retry loop`, use any of the following solutions:

* Upgrade the SSL certificate. On an Ubuntu server, run `update-ca-certificates`. A valid SSL certificate is required to sync training logs securely.
* If the network connection is unstable, operate in offline mode by setting the [optional environment variable](https://docs.coreweave.com/products/wandb/track/environment-variables.md#optional-environment-variables) `WANDB_MODE` to `offline`, and sync files later from a device with internet access.
* Consider using [W\&B Private Hosting](https://docs.coreweave.com/products/wandb/platform/hosting.md), which runs locally and avoids syncing to cloud servers.

If you specifically see the `SSL CERTIFICATE_VERIFY_FAILED` error, the issue might stem from a company firewall intercepting traffic. Point the `requests` library at your local CA bundle so Weights & Biases trusts the firewall's certificate:

```bash theme={"system"}
export REQUESTS_CA_BUNDLE=/etc/ssl/certs/ca-certificates.crt
```

***

[Connectivity](https://docs.coreweave.com/support/models/tags/connectivity.md)