You probably configured the same bucket for uploads and backups before we disallowed it because it’s causing timeouts. Either create a new bucket for backups or append a path to the s3_backup_bucket. Here’s an example of how your settings could look afterwards.
s3_upload_bucket:my-buckets3_backup_bucket:my-bucket/backups
You might want to move existing backups into the new folder. I’m sure DO has something similar to the AWS S3 Console.