diff --git a/argocd/apps/openproject/values-openproject.yaml b/argocd/apps/openproject/values-openproject.yaml
index 5f5e05e..8fdbcab 100644
--- a/argocd/apps/openproject/values-openproject.yaml
+++ b/argocd/apps/openproject/values-openproject.yaml
@@ -43,7 +43,7 @@ spec:
         #
         persistence:
           enabled: true
-          accessMode: ReadWriteOnce
+          accessMode: "ReadWriteOnce"
         s3:
           enabled: false
           auth: