Backblaze Firewall or Network Connection Error

Investigate backup connectivity without weakening security.

Troubleshooting guide · Steps can differ by product, plan and operating system

Understand the issue

Investigate backup connectivity without weakening security. Before making changes, identify the account, affected device or bucket, and the precise symptom. This helps avoid changing settings that are unrelated to the issue.

What to check first

Check whether the computer can reach ordinary websites and whether a proxy, firewall, or managed network is involved.

Determine whether the issue affects one file, one device, a specific network, or the entire account. Write down any exact warning text, the approximate time it started, and the most recent change to your computer or storage configuration.

Step-by-step troubleshooting

1. Identify the product involved: the relevant Backblaze product. Computer Backup and B2 Cloud Storage have different settings, billing models and restore workflows.
2. Check whether the computer can reach ordinary websites and whether a proxy, firewall, or managed network is involved.
3. Review documented network requirements and allow necessary outbound traffic through approved policy. Do not disable the entire firewall to test.
4. After each change, repeat a small, safe test rather than making several unrelated changes at once.
5. Confirm the client resumes an authorized connection and uploads a small eligible file.

If the problem continues

Compare the behavior on a second trusted network or device if appropriate. Review account status, software compatibility, available storage, permissions, and any specific error response. A missing restore file, a blocked upload, and a billing restriction can look similar but require different solutions.

For backups, check the application’s latest activity and selected data. For restores, check the backup snapshot and the restore package status. For B2 integrations, capture the relevant HTTP error code and review the key scope, bucket configuration and endpoint without publishing secrets.

How to confirm the solution

Confirm the client resumes an authorized connection and uploads a small eligible file. Use a noncritical test file when possible. For a restore, inspect the contents of the recovered file, not just its name. For B2 storage, verify the object is present and accessible only to the intended users.

Prevent the issue from returning

• Keep the operating system, backup software, and supported integrations current.
• Periodically test restoring a small file rather than relying solely on a successful-backup indicator.
• Review backup exclusions, external-drive connectivity, account billing, and storage retention settings.
• Protect credentials and use the least privileges needed for cloud-storage integrations.

Frequently asked questions

Will these steps work for both Backblaze products?

Not necessarily. Computer Backup is designed for supported computer backup workflows, while B2 is object storage accessed through buckets, APIs, or integrations. Follow the instructions for your actual product.

Should I uninstall the app or delete my bucket to fix the issue?

No. First check configuration, access, and recoverability. Removing software or deleting storage before verifying your data can make recovery harder or impossible.

What information is useful when asking for help?

Provide the product, operating system or integration, exact error message, approximate time, and the troubleshooting steps already attempted. Never share encryption keys, passwords, or access tokens.

Related Backblaze guides

• Backblaze Backup Stuck or Not Progressing
• Backblaze Not Backing Up New Files
• Backblaze Backup Slow: How to Troubleshoot
• Backblaze App Not Opening on Windows
• Backblaze App Not Opening on Mac