diff --git a/backend/services/clickTtTournamentRegistrationService.js b/backend/services/clickTtTournamentRegistrationService.js
index 5f23b62d..1da4b99c 100644
--- a/backend/services/clickTtTournamentRegistrationService.js
+++ b/backend/services/clickTtTournamentRegistrationService.js
@@ -1,4 +1,6 @@
 import { chromium } from 'playwright';
+import { mkdir, writeFile } from 'fs/promises';
+import path from 'path';
 import Club from '../models/Club.js';
 import ClickTtAccount from '../models/ClickTtAccount.js';
 import OfficialTournament from '../models/OfficialTournament.js';
@@ -58,6 +60,15 @@ function parseDmyRange(value) {
   };
 }
 
+function buildDebugHtmlPath() {
+  const timestamp = new Date().toISOString().replace(/[:.]/g, '-');
+  return path.join(process.cwd(), 'tmp', `clicktt-tournament-debug-${timestamp}.html`);
+}
+
+function sanitizePageText(text) {
+  return String(text || '').replace(/\s+/g, ' ').trim().slice(0, 500);
+}
+
 class ClickTtTournamentRegistrationService {
   async autoRegisterPendingParticipants({ userToken, userId, clubId, tournamentId }) {
     await checkAccess(userToken, clubId);
@@ -134,6 +145,7 @@ class ClickTtTournamentRegistrationService {
     let context = null;
     let page = null;
     const trace = [];
+    let resultsPageUrl = null;
 
     try {
       browser = await chromium.launch({
@@ -154,7 +166,7 @@ class ClickTtTournamentRegistrationService {
       await clickTtPlayerRegistrationService._selectClubContext(page, associationMemberNumber, trace);
       await this._openTournamentSearch(page, trace);
       await this._filterTournamentSearch(page, tournament, trace);
-      const resultsPageUrl = page.url();
+      resultsPageUrl = page.url();
 
       const processedCompetitions = [];
       for (const group of competitionGroups) {
@@ -197,9 +209,49 @@ class ClickTtTournamentRegistrationService {
         competitions: processedCompetitions
       };
     } catch (error) {
-      throw error instanceof HttpError
-        ? error
-        : new HttpError(`Click-TT-Turnieranmeldung fehlgeschlagen: ${error.message || error}`, 500);
+      const diagnostics = {
+        url: null,
+        text: null,
+        htmlPath: null,
+        resultsPageUrl
+      };
+
+      try {
+        const html = await page?.content?.();
+        const htmlPath = html ? buildDebugHtmlPath() : null;
+        if (html && htmlPath) {
+          await mkdir(path.dirname(htmlPath), { recursive: true });
+          await writeFile(htmlPath, html, 'utf8');
+          diagnostics.htmlPath = htmlPath;
+        }
+      } catch (_err) {
+        // keep partial diagnostics
+      }
+
+      try {
+        diagnostics.url = page?.url?.() || null;
+      } catch (_err) {
+        // ignore
+      }
+
+      try {
+        diagnostics.text = sanitizePageText(await page?.locator?.('body')?.innerText?.());
+      } catch (_err) {
+        // ignore
+      }
+
+      const baseMessage = error instanceof HttpError
+        ? error.message
+        : `Click-TT-Turnieranmeldung fehlgeschlagen: ${error.message || error}`;
+      const wrappedError = new HttpError(
+        `${baseMessage}${diagnostics.url ? ` (Seite: ${diagnostics.url})` : ''}${diagnostics.htmlPath ? ` (HTML: ${diagnostics.htmlPath})` : ''}${diagnostics.text ? ` - ${diagnostics.text}` : ''}`,
+        error.statusCode || error.status || 500
+      );
+      wrappedError.htmlPath = diagnostics.htmlPath || null;
+      wrappedError.details = {
+        resultsPageUrl: diagnostics.resultsPageUrl || null
+      };
+      throw wrappedError;
     } finally {
       if (context) {
         try { await context.close(); } catch (_err) {}
diff --git a/frontend/src/views/OfficialTournaments.vue b/frontend/src/views/OfficialTournaments.vue
index f9a28be5..c1a63f1b 100644
--- a/frontend/src/views/OfficialTournaments.vue
+++ b/frontend/src/views/OfficialTournaments.vue
@@ -885,6 +885,9 @@ export default {
         const response = await apiClient.post(
           `/official-tournaments/${this.currentClub}/${this.uploadedId}/auto-register`
         );
+        if (!response?.data?.success) {
+          throw new Error(response?.data?.error || 'Die automatische click-TT-Anmeldung ist fehlgeschlagen.');
+        }
         await this.reload();
         await this.showInfo(
           'Erfolg',
@@ -1567,4 +1570,3 @@ th, td { border-bottom: 1px solid var(--border-color); padding: 0.5rem; text-ali
   }
 }
 </style>
-