I have that same error as well and have been working with Jamie to figure out a solution so that it doesn’t report that it fails. The backups simply aren’t uploading the dom and info files but are still uploading the actual important compressed tar.gz backup files for me.
It appears that the file names may get uploaded strangely according to this post where the person was using Linode object storage and having the same issue: How to debug failed backup - #11 by tomcameron
I also have set the size to 100. I have setup the aws command but had to do some other things like use an alias in ~/.bash_alias and set the region to EU in the ~/.aws/config and make sure it’s using the right credentials in the ~/.aws/credentials.
~/.aws/config
[default]
region = EU
~/.bash_alias
alias aws='aws --endpoint-url https://eu2.contabostorage.com/'
S3-compatible server hostname: eu2.contabostorage.com
Upload chunk size in MB: 100