Generally speaking, most issues are caused by incorrectly entering a configuration item. Make sure that there are no typos and that you are specifying the correct bucket name, region and keys.

If you specify a region that does not match where the bucket or keys exist then you may see an error such as:

The bucket you are attempting to access must be addressed using the specified endpoint.

Make sure that you choose the correct AWS region that corresponds to the location of the bucket and keys.

Be aware of case sensitivity differences when copying, moving, or syncing files and folders between Amazon S3 and other storage locations. Amazon S3 is a case sensitive system whereas other systems are not. This can cause files to be overwritten, and folders to have their contents merged, if their case insensitive names are a match.

Subfolder-Only Permission

If your S3 user policy does not have access to the entire bucket, or is restricted to specific subfolders only, then verification of access to the bucket may fail when testing credentials.

Use the advanced setting for Can these credentials access the root of this remote or are they restricted to a subfolder? to specify a subfolder that can be used to verify access when testing your credentials.

S3 Bucket Access Permission Issues

Access to your S3 bucket is determined by the policies and permissions in Amazon S3. If your IAM policy is too restrictive, or contains errors in the details about the IAM user or Actions, then your Files.com site may not be able to interact correctly with your S3 bucket.

To troubleshoot, configure your IAM policy with the least restrictive possible options and re-test. Incrementally apply changes to the IAM policy to determine which change or option is causing the access issue.

Below is an example S3 user policy that provides full access permissions to your Files.com site (replace <bucketname> with your bucket name):

{
   "Version":"2012-10-17",
   "Statement":[
      {
         "Effect":"Allow",
         "Action": "s3:*",
         "Resource": [
           "arn:aws:s3:::<bucketname>",
           "arn:aws:s3:::<bucketname>/*"
         ]
      }
   ]
}