Snapshot to S3 "unexpected error"

Hi,

I have a Grafana instance on AWS EC2 and need to publish snapshots to S3 however i’m getting “Unexpected Error” when attempting to do so. I’m assuming i’ve got the config slightly wrong (below)?

Grafana v 5.2.2

#################################### Snapshots ###########################
[snapshots]
;snapshot sharing options
external_enabled = true
external_snapshot_url = https://s3.eu-west-2.amazonaws.com
external_snapshot_name = Publish to S3

#################################### External image storage ##########################
[external_image_storage]
;Used for uploading images to public servers so they can be included in slack/email messages.
;you can choose between (s3, webdav, gcs, azure_blob, local)
provider = s3

[external_image_storage.s3]
bucket = ha-grafana-test
region = eu-west-2
path = snapshots
<Access / Secret key> removed.

The access keys for the S3 bucket have full write / read permissions; the bucket however doesn’t have public read access. Bucket URL is https://s3.eu-west-2.amazonaws.com/ha-grafana-test/snapshots/

/var/log/grafana/grafana.log shows no errors

Thanks