UpdraftPlus S3 Integration Not Uploading Backups and the API Key + Bucket Policy Adjustment That Restored Cloud Storage

For many WordPress administrators, UpdraftPlus is a trusted backup plugin that reliably pushes entire site backups to remote destinations like Amazon S3. But what happens when those uploads silently fail? Recently, a persistent issue emerged disrupting automatic transfers to S3, despite correctly configured settings. This article explains what caused the failed backups, how AWS policies and API keys played a crucial role, and walks you through the resolution that restored consistent S3 uploads.

TL;DR (Too Long; Didn’t Read)

If your UpdraftPlus backups are not uploading to Amazon S3, don’t panic. The issue may stem from overly restrictive IAM policies or forgotten API key permissions on the S3 bucket. After thorough investigation and log analysis, revising the bucket policy and recreating the correct API key with full access permissions to the bucket resolved the problem. Restoring backups to S3 was possible within minutes once permissions and policy alignment were correctly implemented.

Understanding the Problem: Silent S3 Upload Failures

UpdraftPlus typically performs scheduled backups and pushes them seamlessly to various cloud services. However, in some environments, recent updates to cloud provider policies or expired API keys can break this automation without any visible frontend errors. That’s exactly what happened in this case, leading to backups being created locally but never making it to the S3 bucket.

There were no warnings in WordPress’ dashboard, but inspecting the UpdraftPlus logs under wp-content/updraft/log.*.txt revealed repeated entries such as:

ERROR: Failed to upload to S3 (403 Forbidden)
Permission Denied: Unable to access the S3 bucket.

In many cases, the root causes of this failure include:

Expired or regenerated AWS API access keys
Incorrect IAM permissions for the S3 API user
Restrictive or misconfigured S3 bucket policies

Initial Debug: Reviewing UpdraftPlus Settings

The first step was double-checking the configuration within the WordPress admin panel:

Go to Settings > UpdraftPlus Backups > Settings.
Under Choose your remote storage, ensure Amazon S3 is selected.
Verify the Access Key and Secret Key are correctly entered.
Ensure the correct S3 bucket and region are selected.

These values hadn’t changed, but something was causing connection failures. When testing the connection (via the “Test S3 Settings” button), the plugin returned a vague error, referencing forbidden access rights.

This meant one critical factor needed attention: the authentication layer and access policies connecting UpdraftPlus to AWS S3.

The Role of AWS: Digging into Permissions and API Keys

Each time UpdraftPlus attempts to communicate with an S3 bucket, it does so using AWS API calls that require correct authentication and authorization. Two things matter most here:

Access Keys: These are credentials created via AWS IAM (Identity and Access Management) used by UpdraftPlus to make requests to S3’s API.
Bucket Policy: A JSON-based configuration that governs who can access a specific S3 bucket.

Upon logging into the AWS Management Console and navigating to IAM > Users > [BackupUser], it was discovered that the Access Key had been deactivated. Perhaps due to security rotation or scheduled expiration.

Furthermore, the existing bucket policy (viewed under S3 > BucketName > Permissions > Bucket Policy) had been narrowed to restrict uploads from certain IP addresses that no longer matched the server’s public IP.

Recreating and Reauthorizing the API Key

To fix the API key issue:

Navigate to AWS Console > IAM > Users > BackupUser.
Under the Security Credentials tab, click Create access key.
Copy the new Access Key ID and Secret Access Key immediately—Secret Keys are shown only once!
Return to the WordPress admin and re-enter the new values in UpdraftPlus settings.

[p>Even after inserting the new keys, testing the connection still showed “Forbidden.” This indicated that either:

The new key wasn’t granted adequate permissions
The bucket policy was continuing to block uploads

Ensuring IAM Permissions Are Correct

Navigate back to the IAM section and verify the attached policy for the API user. It’s critical that it includes at least the following:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "s3:PutObject",
        "s3:GetObject",
        "s3:ListBucket"
      ],
      "Resource": [
        "arn:aws:s3:::your-bucket-name",
        "arn:aws:s3:::your-bucket-name/*"
      ]
    }
  ]
}

Apply and save these changes. Then ensure no conflicting Deny statements exist within any other IAM policies or SCPs (Service Control Policies) if Organizations are used.

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Fixing the S3 Bucket Policy

Even with correct IAM user permissions, the S3 bucket policy itself can override or block access. The following is an example bucket policy that allows access for a specific IAM user and bucket:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AllowUpdraftAccess",
      "Effect": "Allow",
      "Principal": {
        "AWS": "arn:aws:iam::123456789012:user/BackupUser"
      },
      "Action": [
        "s3:PutObject",
        "s3:GetObject"
      ],
      "Resource": "arn:aws:s3:::your-bucket-name/*"
    }
  ]
}

Make sure this bucket doesn’t include any "Condition": {"IpAddress"} clause that restricts by IP unless necessary. In our case, the previous clause had restricted uploads to a retired IP range.

Success: Backup Uploads Restored

Once the bucket policy and IAM permissions were properly aligned and a fresh API key had been generated and saved into UpdraftPlus, everything began to work again. A test backup uploaded successfully, and log files stopped showing permission errors.

Within the UpdraftPlus dashboard:

New backups listed “Upload: OK” under the log summary
Amazon S3 Test Connection returned: Success: You have access to your Amazon S3 bucket
The S3 console visibly included the new backup archives in the correct folder

Conclusion: Prevention Tips and Future Best Practices

This incident is a reminder that cloud integrations are only as strong as their IAM credentials and policy design. Even if UpdraftPlus doesn’t report visible front-end errors, behind-the-scenes failures can put your entire backup strategy at risk. Here are several key takeaways:

Regularly Rotate AWS API Keys: But don’t forget to update connected applications like WordPress.
Always Align IAM and Bucket Policies: Make sure they don’t conflict or override one another.
Monitor Logs Routinely: UpdraftPlus maintains detailed logs for every backup event; check them monthly.
Use Unique IAM Users per Application: This limits blast radius and helps isolate permissions by function.
Enable S3 Event Notifications: Get notified when Updraft fails or when a backup upload completes.

Maintaining a secure and reliable backup strategy is essential for business continuity, security, and peace of mind. By giving appropriate attention to your API keys, permissions, and monitoring, you can ensure that your UpdraftPlus + S3 integration continues to serve as the dependable foundation of your WordPress disaster recovery plan.

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