diff --git a/src/app/api/geoportal/monitor/route.ts b/src/app/api/geoportal/monitor/route.ts
index 9d40dec..392259f 100644
--- a/src/app/api/geoportal/monitor/route.ts
+++ b/src/app/api/geoportal/monitor/route.ts
@@ -10,6 +10,10 @@ export const dynamic = "force-dynamic";
 const TILE_CACHE_INTERNAL = "http://tile-cache:80";
 const MARTIN_INTERNAL = "http://martin:3000";
 const PMTILES_URL = process.env.NEXT_PUBLIC_PMTILES_URL || "";
+// Server-side fetch needs absolute URL — resolve relative paths through tile-cache
+const PMTILES_FETCH_URL = PMTILES_URL.startsWith("/")
+  ? `${TILE_CACHE_INTERNAL}${PMTILES_URL.replace(/^\/tiles/, "")}`
+  : PMTILES_URL;
 const N8N_WEBHOOK_URL = process.env.N8N_WEBHOOK_URL || "";
 
 type NginxStatus = {
@@ -88,7 +92,7 @@ export async function GET() {
   // 3. PMTiles info
   if (PMTILES_URL) {
     try {
-      const res = await fetchWithTimeout(PMTILES_URL, 3000);
+      const res = await fetchWithTimeout(PMTILES_FETCH_URL, 3000);
       result.pmtiles = {
         url: PMTILES_URL,
         status: res.ok ? "ok" : `HTTP ${res.status}`,
@@ -138,7 +142,7 @@ export async function GET() {
 async function getPmtilesInfo(): Promise<{ size: string; lastModified: string } | null> {
   if (!PMTILES_URL) return null;
   try {
-    const res = await fetchWithTimeout(PMTILES_URL, 3000);
+    const res = await fetchWithTimeout(PMTILES_FETCH_URL, 3000);
     return {
       size: res.headers.get("content-length")
         ? `${(parseInt(res.headers.get("content-length") ?? "0", 10) / 1024 / 1024).toFixed(1)} MB`