diff --git a/pbs-api-types/src/datastore.rs b/pbs-api-types/src/datastore.rs
index b2ef001b..7b279084 100644
--- a/pbs-api-types/src/datastore.rs
+++ b/pbs-api-types/src/datastore.rs
@@ -632,7 +632,7 @@ impl BackupNamespace {
         }
 
         if !crate::PROXMOX_SAFE_ID_REGEX.is_match(&subdir) {
-            bail!("not a valid namespace component");
+            bail!("not a valid namespace component: {subdir}");
         }
 
         if !self.inner.is_empty() {