diff --git a/server/vbv_lernwelt/course/admin.py b/server/vbv_lernwelt/course/admin.py
index ab5d2bbe..31773f6b 100644
--- a/server/vbv_lernwelt/course/admin.py
+++ b/server/vbv_lernwelt/course/admin.py
@@ -48,6 +48,7 @@ class CourseSessionUserAdmin(admin.ModelAdmin):
         "course_session",
         "role",
     ]
+    raw_id_fields = ["user", ]
 
     fieldsets = [
         (None, {"fields": ("user", "course_session", "role")}),
diff --git a/server/vbv_lernwelt/importer/services.py b/server/vbv_lernwelt/importer/services.py
index 1728a6bf..7e53de5f 100644
--- a/server/vbv_lernwelt/importer/services.py
+++ b/server/vbv_lernwelt/importer/services.py
@@ -171,7 +171,7 @@ def create_or_update_trainer(course: Course, data: Dict[str, Any], language="de"
     )
 
     user = create_or_update_user(
-        email=data["Email"],
+        email=data["Email"].lower(),
         first_name=data["Vorname"],
         last_name=data["Name"],
     )
@@ -250,7 +250,7 @@ def create_or_update_student(data: Dict[str, Any]):
     )
 
     user = create_or_update_user(
-        email=data["Email"],
+        email=data["Email"].lower(),
         first_name=data["Vorname"],
         last_name=data["Name"],
     )
diff --git a/server/vbv_lernwelt/sso/views.py b/server/vbv_lernwelt/sso/views.py
index 98aa587e..957a1b8e 100644
--- a/server/vbv_lernwelt/sso/views.py
+++ b/server/vbv_lernwelt/sso/views.py
@@ -37,7 +37,7 @@ def authorize(request):
 
     user_data = _user_data_from_token_data(decoded_token)
     user = create_or_update_user(
-        email=user_data.get("email"),
+        email=user_data.get("email").lower(),
         sso_id=user_data.get("sso_id"),
         first_name=user_data.get("first_name", ""),
         last_name=user_data.get("last_name", ""),