diff --git a/Website/main.py b/Website/main.py
index 7f6156c..1625a8a 100644
--- a/Website/main.py
+++ b/Website/main.py
@@ -2298,7 +2298,8 @@ def background_booking_provisioning(
                         address=address,
                         price=price,
                         date=formatted_date,
-                        software_name=software_name
+                        software_name=software_name,
+                        user_id=username
                     )
 
             except Exception as mail_err:
@@ -2538,7 +2539,7 @@ def booking_payment():
                     username, 
                     address_process, 
                     price_str, 
-                    selected_package 
+                    selected_package,
                 )
             )
             thread.start()
@@ -3506,7 +3507,8 @@ def test_email():
             address="Test Address 123, 12345 Test City",
             price="200",
             date="Test City, 01.01.2023",
-            software_name="starter"
+            software_name="starter",
+            user_id="test_user_id"
         )
         return "Test email sent successfully."
     except Exception as e:
diff --git a/Website/modules/emailservice/email.py b/Website/modules/emailservice/email.py
index 30d7218..98d4bf3 100644
--- a/Website/modules/emailservice/email.py
+++ b/Website/modules/emailservice/email.py
@@ -460,6 +460,7 @@ def send_accreditation_email(
     domain: str, 
     username: str, 
     password: str, 
+    user_id: str,
     school_name: str = "[Name der Schule / des Auftraggebers]",
     address: str = "[Straße, Hausnummer] [PLZ, Ort]",
     price: str = "250,00",
@@ -646,7 +647,7 @@ def send_accreditation_email(
     # Wir nutzen hier die übergebenen Funktionsparameter anstatt des undefinierten "prov"
     col.insert_one(
         {
-            "username": username,
+            "username": user_id,
             "school_name": school_name,       
             "address": address,               
             "invoice_number": current_invoice_number, 
@@ -663,7 +664,7 @@ def send_accreditation_email(
     )
 
     req_col.update_one(
-        {"username": username}, 
+        {"username": user_id}, 
         {"$set": {
             "provision_status": "invoice_created", 
             "updated_at": _utc_now_iso()