diff --git a/server.ts b/server.ts
index 8f8bdb6..ca5f7fe 100644
--- a/server.ts
+++ b/server.ts
@@ -125,6 +125,10 @@ async function startServer() {
       const token = jwt.sign({ userId: row.id, email: row.email }, JWT_SECRET, { expiresIn: JWT_EXPIRY });
       const user: User = { id: row.id, name: row.name, role: row.role, email: row.email };
 
+      const logId = uid("log");
+      db.prepare(`INSERT INTO logs (id, timestamp, type, message, deviceId, userId) VALUES (?, ?, ?, ?, ?, ?)`)
+        .run(logId, new Date().toISOString(), 'system', `${row.name} logged in.`, null, row.id);
+
       res.json({ token, user });
     } catch (err: any) {
       res.status(500).json({ error: err.message });
@@ -686,36 +690,51 @@ async function startServer() {
   // in Settings take effect on the next cycle without a server restart.
   // -------------------------------------------------------------
   async function syncCheckMkStatuses() {
+    const now = new Date().toISOString();
+
     if (getSetting('checkmk_enabled') !== 'true') return;
+
     const CHECKMK_API_URL = getSetting('checkmk_api_url') || process.env.CHECKMK_API_URL;
     const CHECKMK_API_USER = getSetting('checkmk_api_user') || process.env.CHECKMK_API_USER || 'automation';
     const CHECKMK_API_SECRET = getSetting('checkmk_api_secret') || process.env.CHECKMK_API_SECRET;
-    if (!CHECKMK_API_URL || !CHECKMK_API_SECRET) return;
+
+    if (!CHECKMK_API_URL || !CHECKMK_API_SECRET) {
+      db.prepare('INSERT INTO logs (id, timestamp, type, message) VALUES (?, ?, ?, ?)')
+        .run(uid('log'), now, 'system', 'CheckMK sync skipped — API URL or secret not configured. Check Settings.');
+      return;
+    }
+
+    const authHeader = `Bearer ${CHECKMK_API_USER} ${CHECKMK_API_SECRET}`;
 
     // Step 1: build IP → hostname map from CheckMK host configurations
+    // Falls back to effective_attributes for IPs inherited from a parent folder.
     let ipToHostname: Map<string, string>;
     try {
       const cfgRes = await fetch(
         `${CHECKMK_API_URL}/domain-types/host_config/collections/all`,
-        { headers: { Authorization: `Bearer ${CHECKMK_API_USER} ${CHECKMK_API_SECRET}`, Accept: 'application/json' } }
+        { headers: { Authorization: authHeader, Accept: 'application/json' } }
       );
-      if (!cfgRes.ok) throw new Error(`HTTP ${cfgRes.status}`);
+      if (!cfgRes.ok) throw new Error(`HTTP ${cfgRes.status} — ${await cfgRes.text()}`);
       const cfgData = await cfgRes.json();
       ipToHostname = new Map<string, string>();
       for (const host of cfgData?.value ?? []) {
-        const ip: string | undefined = host?.extensions?.attributes?.ipaddress;
+        const ext = host?.extensions;
+        const ip: string | undefined =
+          ext?.attributes?.ipaddress || ext?.effective_attributes?.ipaddress;
         const name: string | undefined = host?.id;
         if (ip && name) ipToHostname.set(ip, name);
       }
-    } catch (err) {
-      console.error('[CheckMK] Failed to fetch host configs:', err);
+    } catch (err: any) {
+      const msg = `CheckMK sync failed — could not fetch host list: ${err?.message ?? err}`;
+      console.error('[CheckMK]', msg);
+      db.prepare('INSERT INTO logs (id, timestamp, type, message) VALUES (?, ?, ?, ?)')
+        .run(uid('log'), now, 'system', msg);
       return;
     }
 
     // Step 2: update each device based on IP lookup and log status changes
     const rows = db.prepare('SELECT id, hostname, ip, status FROM devices').all() as { id: string; hostname: string; ip: string; status: string }[];
     const counts = { online: 0, offline: 0, unknown: 0 };
-    const now = new Date().toISOString();
 
     for (const dev of rows) {
       const cmkHost = ipToHostname.get(dev.ip);
@@ -731,9 +750,9 @@ async function startServer() {
       try {
         const res = await fetch(
           `${CHECKMK_API_URL}/objects/host/${encodeURIComponent(cmkHost)}`,
-          { headers: { Authorization: `Bearer ${CHECKMK_API_USER} ${CHECKMK_API_SECRET}`, Accept: 'application/json' } }
+          { headers: { Authorization: authHeader, Accept: 'application/json' } }
         );
-        if (!res.ok) throw new Error(`HTTP ${res.status}`);
+        if (!res.ok) throw new Error(`HTTP ${res.status} — ${await res.text()}`);
         const data = await res.json();
         const hardState: number = data?.extensions?.state ?? -1;
         const newStatus = hardState === 0 ? 'online' : 'offline';
@@ -743,13 +762,15 @@ async function startServer() {
             .run(uid('log'), now, 'status', `CheckMK: ${dev.hostname} (${dev.ip}) status changed to ${newStatus} (was: ${dev.status}).`, dev.id);
         }
         counts[newStatus as 'online' | 'offline']++;
-      } catch (err) {
-        console.error(`[CheckMK] Status sync failed for ${dev.hostname} (${dev.ip}):`, err);
+      } catch (err: any) {
+        const msg = `CheckMK: status sync failed for ${dev.hostname} (${dev.ip}) — ${err?.message ?? err}`;
+        console.error('[CheckMK]', msg);
+        db.prepare('INSERT INTO logs (id, timestamp, type, message, deviceId) VALUES (?, ?, ?, ?, ?)')
+          .run(uid('log'), now, 'system', msg, dev.id);
         counts.unknown++;
       }
     }
 
-    // Summary log entry for every sync run
     db.prepare('INSERT INTO logs (id, timestamp, type, message) VALUES (?, ?, ?, ?)')
       .run(uid('log'), now, 'system',
         `CheckMK sync completed — ${counts.online} online, ${counts.offline} offline, ${counts.unknown} unknown (${rows.length} devices total).`);