Using default credentials even if there is a credentials folder mounted

[nicktar]

I'm trying to get the proxy running...

Started the docker-container as per the command adapted from the readme (docker run --rm -v ~/.aws:/root/.aws -p 9200:9200 abutaha/aws-es-proxy:v1.5 -endpoint https://dummy-host.ap-southeast-2.es.amazonaws.com -listen 0.0.0.0:9200) with my endpoint and switching the version from 1.0 to 1.5.
Whenever I try to access the instance (via web request or "Multi Elasticsearch Heads"-Plugin) I just get a "Failed to sign".
I checked if the .aws directory is correctly mounted into the container and that it contains the current/correct/working credentials and turned on verbose and debug output.
With these additional log entries, I see

time="2024-22-08 11:18:17" level=info msg="Using default credentials"
time="2024-22-08 11:18:17" level=info msg="Generated fresh AWS Credentials object"
time="2024-22-08 11:18:23" level=error msg="Failed to sign NoCredentialProviders: no valid providers in chain\ncaused by: EnvAccessKeyNotFound: failed to find credentials in the environment.\nSharedCredsLoad: failed to load profile, .\nEC2RoleRequestError: no EC2 instance role found\ncaused by: RequestError: send request failed\ncaused by: Get \"http://xyz.xyz.xyz.xyz/latest/meta-data/iam/security-credentials/\": context deadline exceeded (Client.Timeout exceeded while awaiting headers)

Looks like the proxy isn't picking up the supplied credentials, but I can't figure out why...
What am I doing wrong?