try moving it back

argocd-nginx/base/argocd-ingress.yaml

@@ -3,6 +3,8 @@ kind: Ingress
 metadata:
   name: argocd-ingress
   namespace: argocd
+  annotations:
+    cert-manager.io/issuer: "letsencrypt"
 spec:
   ingressClassName: nginx
   tls:

argocd-nginx/base/cert-manager-issuer.yml

@@ -1,5 +1,5 @@
 apiVersion: cert-manager.io/v1
-kind: ClusterIssuer
+kind: Issuer
 metadata:
   name: letsencrypt
   namespace: cert-manager

argocd-nginx/base/kustomization.yaml

@@ -1,2 +1,3 @@
 resources:
   - argocd-ingress.yaml
+  - cert-manager-issuer.yml

argocd-nginx/overlays/test/argocd-ingress.yaml

@@ -4,7 +4,7 @@ metadata:
   name: argocd-ingress
   namespace: argocd
   annotations:
-    cert-manager.io/cluster-issuer: "letsencrypt"
+    cert-manager.io/issuer: "letsencrypt"
 spec:
   defaultBackend:
     service:

cert-manager/base/kustomization.yaml

@@ -4,4 +4,3 @@ kind: Kustomization
 namespace: cert-manager
 resources:
 - https://github.com/cert-manager/cert-manager/releases/download/v1.16.1/cert-manager.yaml
-- cert-manager-issuer.yml