Video Upload is Failing

The "Access Denied" error you're encountering when uploading a video to AWS S3 is not likely due to multiple upload attempts. This error indicates that the request to upload or access the video is being explicitly denied due to insufficient permissions. There are several potential reasons for this:

1. IAM Permissions: The IAM user or role you're using may not have the necessary permissions to perform the upload operation. Check your IAM policies to ensure they allow the required S3 actions, such as s3:PutObject.

2. Bucket Policy: The S3 bucket may have a policy that's restricting access. Review the bucket policy to make sure it allows the upload operation from your account or IAM entity.

3. S3 Block Public Access: If enabled, this setting can prevent certain operations. Verify that the Block Public Access settings aren't interfering with your upload.

4. Encryption Settings: If the bucket uses server-side encryption with AWS KMS, ensure that your IAM entity has permissions to use the specified KMS key.

5. Object Lock: If S3 Object Lock is enabled on the bucket, it could prevent modifications to objects.

6. VPC Endpoint Policies: If you're using a VPC endpoint to access S3, check that the endpoint policy allows the necessary actions.

7. AWS Organizations Policies: If your account is part of an AWS Organization, there might be service control policies (SCPs) affecting S3 access.

To troubleshoot:

1. Review all applicable policies (IAM, bucket, VPC endpoint, etc.)
2. Check S3 Block Public Access settings
3. Verify encryption settings and KMS key permissions if applicable
4. Ensure your IAM entity has the necessary permissions for the S3 actions you're attempting

If you're using AWS Amplify or a similar service for uploads, also check that the storage configurations and access rules are correctly set up to allow authenticated users to perform write operations.

Remember, just because other videos are displaying correctly doesn't necessarily mean the permissions for uploading new videos are in place. Different operations (like read vs. write) may have different permission requirements.
Sources
Troubleshoot access denied error messages - AWS Identity and Access Management
Troubleshoot access denied (403 Forbidden) errors in Amazon S3 - Amazon Simple Storage Service