fix

index.html

@@ -99,10 +99,11 @@
           
           const code = params.get('code');
           const body = new URLSearchParams({
-            client_id: CLIENT_ID,
             grant_type: 'authorization_code',
             code: code,
-            redirect_uri: REDIRECT_URI
+            redirect_uri: REDIRECT_URI,
+            client_assertion_type: 'urn:ietf:params:oauth:client-assertion-type:jwt-bearer',
+            client_assertion: CLIENT_ID
           });
           
           console.log('Token exchange body:', body.toString());