diff --git a/server/prometheus-service.js b/server/prometheus-service.js
index 5f6c3e7..0d3af14 100644
--- a/server/prometheus-service.js
+++ b/server/prometheus-service.js
@@ -39,13 +39,27 @@ function createClient(baseUrl) {
 async function testConnection(url) {
   const normalized = normalizeUrl(url);
   try {
-    const res = await axios.get(`${normalized}/api/v1/status/buildinfo`, {
-      timeout: QUERY_TIMEOUT,
-      httpAgent,
-      httpsAgent
+    // Using native fetch to avoid follow-redirects/axios "protocol mismatch" issues in some Node environments
+    const controller = new AbortController();
+    const timer = setTimeout(() => controller.abort(), QUERY_TIMEOUT);
+    
+    // Node native fetch - handles http/https automatically
+    const res = await fetch(`${normalized}/api/v1/status/buildinfo`, {
+      signal: controller.signal
     });
-    return res.data?.data?.version || 'unknown';
+    
+    clearTimeout(timer);
+
+    if (!res.ok) {
+      throw new Error(`Prometheus returned HTTP ${res.status}`);
+    }
+    
+    const data = await res.json();
+    return data?.data?.version || 'unknown';
   } catch (err) {
+    if (err.name === 'AbortError') {
+      throw new Error('Connection timed out');
+    }
     console.error(`[Prometheus] Connection test failed for ${normalized}:`, err.message);
     throw err;
   }