So I had trouble setting up S3 backup using the server my provider had available.
They use a custom s3 instance based on:
It is compatible with boto, but in order to have it working with mailinabox, first I had to create /home/user-data/backup/custom.yaml
and then i had to add to /etc/boto3.cfg (not sure why its call boto3 when the box is using latets v2 (after the issue is fixed))
endpoints_path = /path/to/custom_endpoint.json
and there the json file
I’ll check up tomorrow if I find the backup had any problems.
Hope it helps someone,