Docker pull command fails when launched in Jenkins - bash

Question

I am writing a Jenkins pipeline aimed to pull a docker image from a private registry. At the moment I have an issue in launching the docker pull command, since it fails when launched from Jenkins.
Currently, the Jenkins pipeline works as follow:
takes a set of parameters from user (i.e.: image name and tag)
launches a separate bash script performing the pull operation.
The bash script does two operations:
logs in the registry through the following: echo $pwd | docker login -u$username --password-stdin $registryUrl
pulls the image through the command: docker pull $image:$tag
The login command succeeds, while the pull command replies with:
Error response from daemon: access denied:
no access to Image Load, on collection swarm
At first sight I think that's a matter of user privileges, but running the bash script outside the Jenkins context (as the owner of the jenkins process) it works.
Am I missing any configuration? As an alternative, I tried to implement the Jenkins pipeline using the Docker Jenkins Plugin API, but it fails too.
Final Note
The owner of the Jenkins process is different from the user logging in Docker private registry. May this affect the behavior?
Operating System:
macOS 10.14.6
Docker Version details:
Client: Docker Engine - Community
Version: 19.03.4
API version: 1.40
Go version: go1.12.10
Git commit: 9013bf5
Built: Thu Oct 17 23:44:48 2019
OS/Arch: darwin/amd64
Experimental: false
Server: Docker Engine - Community
Engine:
Version: 19.03.4
API version: 1.40 (minimum version 1.12)
Go version: go1.12.10
Git commit: 9013bf5
Built: Thu Oct 17 23:50:38 2019
OS/Arch: linux/amd64

Answer 1

Pipelines have their own commands and tricks to login to dockerhub. For example,
docker.withRegistry('https://registry.hub.docker.com', 'dockerhub-creds') {
docker.image('myteam/secretimage:latest').inside() {
checkout scm
sh './configure && make && make test'
}
}
Here, dockerhub-creds are credentials you should create in Jenkins itself.
This technique is better than echoing password because:
Password will be hidden in build's stdout and from other users who don't have access to credentials
Password is magically mirrored across users, build nodes, docker containers etc and you will not face situation that "execution context is different, nothing works"