GKE Cannot pull image, even though imagesPullSecret is defined - kubernetes

Question

In Google Kubernetes Engine I created a POC cluster for our company which worked flawlessly. But now, when I try to create our production environment I cannot seem to get the imagesPullSecrets to work, it's the exact same credentials as in the POC, Same helm chart and the exact same regcred yaml file.
Yet i keep getting the classical:
Back-off pulling image "registry.company.co/frontend/company-web/upload": ImagePullBackOff
Pulling manually on the node works with the same credentials as those that i supplied in the imagesPullSecret
I've tried defining the imagesPullSecret both on a chart level and on the Service Account
I've verified the secret format and directly copied the credentials there when trying the manual pulls
GKE picks up regcred and shows it in the deployment
Regcred generated by kubectl create secret docker-registry regcred --docker-server="registry.company.co" --docker-username="gitlab" --docker-password="[PASSWORD]"
regcred secret
kind: Secret
apiVersion: v1
metadata:
name: regcred
namespace: default
data:
.dockerconfigjson: eyJhdXRocyI6eyJyZWdpc3RyeS5jb21wYW55LmNvIjp7InVzZXJuYW1lIjoiZ2l0bGFiIiwicGFzc3dvcmQiOiJbUkVEQUNURURdIiwiYXV0aCI6IloybDBiR0ZpT2x0QmJITnZJRkpsWkdGamRHVmtYUT09In19fQ==
type: kubernetes.io/dockerconfigjson
Service Account
kind: ServiceAccount
apiVersion: v1
metadata:
name: default
namespace: default
secrets:
- name: default-token-jktj5
imagePullSecrets:
- name: regcred
Deployment.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: nfs-server
spec:
replicas: 1
selector:
matchLabels:
role: nfs-server
template:
metadata:
labels:
role: nfs-server
spec:
containers:
- name: nfs-server
image: gcr.io/google_containers/volume-nfs:latest
ports:
- name: nfs
containerPort: 2049
- name: mountd
containerPort: 20048
- name: rpcbind
containerPort: 111
securityContext:
privileged: true
volumeMounts:
- mountPath: /exports
name: mypvc
initContainers:
- name: init-volume-perms
imagePullPolicy: Always
image: alpine
command: ["/bin/sh", "-c"]
args: ["mkdir /mnt/company-logos; mkdir /mnt/uploads; chown -R 1337:1337 /mnt"]
volumeMounts:
- mountPath: /mnt
name: mypvc
- name: company-web-uploads
image: registry.company.co/frontend/company-web/uploads
imagePullPolicy: Always
volumeMounts:
- mountPath: /var/lib/company/web/uploads
subPath: uploads
name: mypvc
- name: company-logos
image: registry.company.co/backend/pdf-service/company-logos
imagePullPolicy: Always
volumeMounts:
- mountPath: /var/lib/company/shared/company-logos
subPath: company-logos
name: mypvc
volumes:
- name: mypvc
gcePersistentDisk:
pdName: gke-nfs-disk
fsType: ext4
I've looked around, following different guides from the ground up to no success.
So I'm at a total loss as to what to do.
Default namespace all around

Answer 1

It may be because of namespace issue. Can you verify a few things
Are you using default namespace at both places?
K8S version difference between poc and prod.
Can you recreate working secret by something like kubectl get secret default-token-jktj5 -o yaml > imagepullsecret.yaml. Edit the yaml file to remove revision and other status information. Apply the same to prod
I have seen this issue in GKE because of multiline secret conversion to base64. Ensure secrets are matching between environments.