Unable to pull from docker mirror

I’m trying to configure a mirror for docker hub but every time docker tries to download something from the mirror it fails because:

Attempting next endpoint for pull after error: Get \"\": unauthorized: access to the requested resource is not authorized    

The repository is configured for anonymous pull and the related Docker Bearer Token Realm is listed among the active realms.

has anyone been able to make it working?

nexus version 3.27.0-03 running with podman:

ExecStart=/usr/bin/podman run \
--rm \
--volume /data/nexus:/nexus-data:Z \
--publish 9081:8081 \
--publish 9083:5001 \
--publish 9085:5002 \
--name nexus \

Is the request making it to Nexus? I see an HTTP protocol in your URL and modern Docker really doesn’t want to talk over HTTP

yes it does, here I’ve marked the repository as insecure just for testing but the same happen when I try to access it from a the secure reverse proxy that sits in front of nexus.

$ http https://hub:443/v2/rmohr/activemq/manifests/5.15.9-alpine
HTTP/1.1 401 Unauthorized
Content-Length: 113
Content-Security-Policy: sandbox allow-forms allow-modals allow-popups allow-presentation allow- scripts allow-top-navigation
Content-Type: application/json
Date: Fri, 23 Oct 2020 16:50:44 GMT
Docker-Distribution-Api-Version: registry/2.0
Server: Caddy
Server: Nexus/3.27.0-03 (OSS)
Www-Authenticate: Bearer realm="https://hub/v2/token",service="https://hub/v2/token"
X-Content-Type-Options: nosniff
X-Xss-Protection: 1; mode=block

    "errors": [
            "code": "UNAUTHORIZED",
            "detail": null,
            "message": "access to the requested resource is not authorized"