diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6afab76..3a53b69 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## v0.2.2 (2026-03-28)
 
+### Bug Fixes
+
+- **Test Connection always showed "success"**: frontend never checked the `success` field
+  returned by the backend — any HTTP 200 response (including `{success: false}`) was
+  displayed as "Connection successful!". Now the actual `success` value is checked and
+  authentication failures are shown as errors with the server's message.
+- **Test Connection in edit mode required password re-entry**: added backend endpoint
+  `POST /mail-accounts/{account_id}/test` that decrypts and uses the stored credentials
+  so existing accounts can be tested without re-typing the password.
+
+
+
 ### Bug Fixes
 
 - Resolve semantic-release CHANGELOG.md not updating properly
diff --git a/backend/app/api/v1/endpoints/mail_accounts.py b/backend/app/api/v1/endpoints/mail_accounts.py
index a846041..7c9c9bf 100644
--- a/backend/app/api/v1/endpoints/mail_accounts.py
+++ b/backend/app/api/v1/endpoints/mail_accounts.py
@@ -8,7 +8,7 @@ from sqlalchemy import select, desc, func
 
 from app.core.database import get_db
 from app.core.deps import get_current_active_user
-from app.core.security import encrypt_credential
+from app.core.security import encrypt_credential, decrypt_credential
 from app.models.database_models import (
     User,
     MailAccount,
@@ -269,6 +269,39 @@ async def test_mail_connection(
     return MailAccountTestResponse(success=success, message=message)
 
 
+@router.post("/{account_id}/test", response_model=MailAccountTestResponse)
+async def test_existing_mail_connection(
+    account_id: int,
+    current_user: User = Depends(get_current_active_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Test connection for an existing mail account using its stored credentials"""
+    result = await db.execute(
+        select(MailAccount).where(
+            MailAccount.id == account_id, MailAccount.user_id == current_user.id
+        )
+    )
+    account = result.scalar_one_or_none()
+
+    if not account:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND, detail="Mail account not found"
+        )
+
+    try:
+        password = decrypt_credential(account.encrypted_password)
+    except Exception:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail="Failed to decrypt stored credentials",
+        )
+
+    processor = MailProcessor(account, password)
+    success, message = await processor.test_connection()
+
+    return MailAccountTestResponse(success=success, message=message)
+
+
 @router.post("/auto-detect", response_model=MailAccountAutoDetectResponse)
 async def auto_detect_mail_settings(
     detect_request: MailAccountAutoDetectRequest,
diff --git a/docs/TODO.md b/docs/TODO.md
index cebd7e5..a563c72 100644
--- a/docs/TODO.md
+++ b/docs/TODO.md
@@ -17,7 +17,8 @@ Comprehensive task breakdown for repository improvements and production readines
 - [x] Added GitOps auto-deployment step in `ci.yml` to update preprod k8s manifest in `k8s-cluster-state` repo.
 - [x] Fixed GitOps `update-k8s-manifest` job: added PAT availability check to skip gracefully when `GH_PAT` secret is not configured, fixing 403 "Write access to repository not granted" pipeline failure.
 - [x] Fixed Celery `TypeError: can't subtract offset-naive and offset-aware datetimes` in `process_all_enabled_accounts` — all mail accounts were silently skipped on every scheduled run.
-- [x] Changed Celery beat schedule to run `process_all_enabled_accounts` every minute so accounts configured with `check_interval_minutes = 1` are polled as expected.
+- [x] Fixed **Test Connection** always reporting success regardless of authentication outcome.
+- [x] Added `POST /mail-accounts/{account_id}/test` endpoint to test existing accounts with stored credentials.
 
 ## 🔴 Critical - Security (In Progress)
 
diff --git a/frontend/src/components/AddMailAccountModal.tsx b/frontend/src/components/AddMailAccountModal.tsx
index 30059ef..16f12de 100644
--- a/frontend/src/components/AddMailAccountModal.tsx
+++ b/frontend/src/components/AddMailAccountModal.tsx
@@ -115,24 +115,37 @@ export function AddMailAccountModal({ account, onClose }: AddMailAccountModalPro
   };
 
   const handleTestConnection = async () => {
-    if (!formData.username || !formData.password || !formData.host) {
-      alert('Please fill in username, password, and host');
-      return;
-    }
-
     setTestStatus('testing');
     setTestMessage('');
     try {
-      await mailAccountsApi.test({
-        protocol: formData.protocol,
-        host: formData.host,
-        port: formData.port,
-        username: formData.username,
-        password: formData.password,
-        use_ssl: formData.use_ssl,
-      });
-      setTestStatus('success');
-      setTestMessage('Connection successful!');
+      let result: { success: boolean; message: string };
+
+      if (isEditMode && !formData.password && account?.id) {
+        // Edit mode with no new password entered — test using stored credentials
+        result = await mailAccountsApi.testExisting(account.id);
+      } else {
+        if (!formData.username || !formData.password || !formData.host) {
+          setTestStatus('error');
+          setTestMessage('Please fill in username, password, and host');
+          return;
+        }
+        result = await mailAccountsApi.test({
+          protocol: formData.protocol,
+          host: formData.host,
+          port: formData.port,
+          username: formData.username,
+          password: formData.password,
+          use_ssl: formData.use_ssl,
+        });
+      }
+
+      if (result.success) {
+        setTestStatus('success');
+        setTestMessage(result.message);
+      } else {
+        setTestStatus('error');
+        setTestMessage(result.message || 'Connection failed');
+      }
     } catch (error) {
       setTestStatus('error');
       const errorMessage = error instanceof Error && 'response' in error
diff --git a/frontend/src/lib/api.ts b/frontend/src/lib/api.ts
index 8dfc15a..1c61637 100644
--- a/frontend/src/lib/api.ts
+++ b/frontend/src/lib/api.ts
@@ -338,6 +338,13 @@ export const mailAccountsApi = {
     return response.data;
   },
 
+  async testExisting(accountId: number): Promise<{ success: boolean; message: string }> {
+    const response = await api.post<{ success: boolean; message: string }>(
+      `/mail-accounts/${accountId}/test`
+    );
+    return response.data;
+  },
+
   async autoDetect(
     emailAddress: string
   ): Promise<{ success: boolean; suggestions: AutoDetectSuggestion[] }> {