External Image Store not working [S3]

Hi,

i am using docker-compose stack and try to configure an external image store.

S3:

- GF_EXTERNAL_IMAGE_STORAGE_PROVIDER=s3
- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET_URL=https://grafanaxxxxxxxxxx.s3-eu-central-1.amazonaws.com
- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET=grafanaxxxxxxxxxx
- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET_REGION=s3-eu.central-1
#- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET_PATH=
- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET_ACCESS_KEY=XXXMYACCESSKEYXXX
- GF_EXTERNAL_IMAGE_STORAGE_S3_BUCKET_SECRET_KEY=XXXMYSECRETKEYXXX

The Error for S3 configuration is:

msg=“Failed to upload alert panel image.” logger=alerting.notifier error=“NoCredentialProviders: no valid providers in chain. Deprecated.\n\tFor verbose messaging see aws.Config.CredentialsChainVerboseErrors”

Anybody here how can help me to configure the store? Thanks!