There are two policies to choose from. The first policy is for use when immutability is not used for the cloud tier. The second policy is for use when immutability is used for the cloud tier.
Use the following JSON for non-immutable buckets to create an IAM Policy. These permissions will allow the Veeam Backup Service to access the S3 repository to save/load data to/from an object repository.
Note: Replace yourbucketname (lines 16 and 17) with the actual bucket name.