diff --git a/pdf_renamer.py b/pdf_renamer.py
index 87433d9..28b4813 100644
--- a/pdf_renamer.py
+++ b/pdf_renamer.py
@@ -29,14 +29,25 @@ print(f"DEBUG: CLIENT_SECRET = {'*' * len(CLIENT_SECRET) if CLIENT_SECRET else '
 ADMIN_USERNAME = os.getenv('ADMIN_USERNAME', 'trbcit')
 ADMIN_PASSWORD = os.getenv('ADMIN_PASSWORD', 'atdrmbicn')
 
+# Initialize OAuth
 oauth = OAuth(app)
-microsoft = oauth.register(
-    name='microsoft',
-    client_id=CLIENT_ID,
-    client_secret=CLIENT_SECRET,
-    server_metadata_url=f'https://login.microsoftonline.com/{TENANT_ID}/v2.0/.well-known/openid_configuration',
-    client_kwargs={'scope': 'openid email profile'}
-)
+
+# Register Microsoft OAuth provider with proper configuration
+try:
+    microsoft = oauth.register(
+        name='microsoft',
+        client_id=CLIENT_ID,
+        client_secret=CLIENT_SECRET,
+        server_metadata_url=f'https://login.microsoftonline.com/{TENANT_ID}/v2.0/.well-known/openid-configuration',
+        client_kwargs={
+            'scope': 'openid email profile',
+            'token_endpoint_auth_method': 'client_secret_post'
+        }
+    )
+    print("DEBUG: Microsoft OAuth provider registered successfully")
+except Exception as e:
+    print(f"ERROR: Failed to register Microsoft OAuth provider: {e}")
+    microsoft = None
 
 def analyze_failed_extractions(log_path):
     """
@@ -654,6 +665,11 @@ def login():
 
 @app.route('/entra-login')
 def entra_login():
+    # Check if Microsoft OAuth provider is available
+    if microsoft is None:
+        flash('Microsoft Entra ID authentication is not configured.', 'error')
+        return redirect(url_for('login'))
+    
     # Check if Microsoft Entra ID is configured
     if TENANT_ID in ['your-tenant-id', 'YOUR_MICROSOFT_ENTRA_TENANT_ID'] or \
        CLIENT_ID in ['your-client-id', 'YOUR_MICROSOFT_ENTRA_CLIENT_ID'] or \
@@ -661,8 +677,16 @@ def entra_login():
         flash('Microsoft Entra ID is not properly configured. Please check your environment variables.', 'error')
         return redirect(url_for('login'))
 
-    redirect_uri = url_for('auth', _external=True)
-    return microsoft.authorize_redirect(redirect_uri)
+    try:
+        redirect_uri = url_for('auth', _external=True)
+        print(f"DEBUG: Initiating OAuth with redirect_uri: {redirect_uri}")
+        return microsoft.authorize_redirect(redirect_uri)
+    except Exception as e:
+        print(f"ERROR: Failed to initiate OAuth: {e}")
+        import traceback
+        print(f"Traceback: {traceback.format_exc()}")
+        flash('Failed to initiate Microsoft authentication. Please try again or use admin login.', 'error')
+        return redirect(url_for('login'))
 
 @app.route('/admin-login', methods=['POST'])
 def admin_login():