diff --git a/samy.js b/samy.js
index cfe82cc..c214036 100644
--- a/samy.js
+++ b/samy.js
@@ -240,6 +240,14 @@ async function fetchSites() {
     if (!resp.ok) throw "HTTP " + resp.status;
 
     const sites = await resp.json();
+
+    if (!Array.isArray(sites) || sites.length === 0) {
+      dropdown.innerHTML =
+        '<option disabled selected>No sites returned</option>';
+      alert("No Datto sites returned. Verify credentials/allowlist, or try again in a moment.");
+      return;
+    }
+    
     dropdown.innerHTML = "";
 
     sites.forEach((site) => {