diff --git a/main.py b/main.py
index 2eb6d8a..d0b0db6 100755
--- a/main.py
+++ b/main.py
@@ -104,6 +104,8 @@ def append_extra_group_fields_to_ldap_user(ldap_user: WritableEntry, dolibarr_us
 
     user_id = dolibarr_user['id']
     dolibarr_groups: list[dict] = dolibarr_client.get_user_groups_uid(user_id)
+    if not isinstance(dolibarr_groups, list):
+        dolibarr_groups = []
     if oldgroupid:
         dolibarr_groups = [group for group in dolibarr_groups if group['id'] != oldgroupid]
     if newgroupid:
@@ -111,6 +113,9 @@ def append_extra_group_fields_to_ldap_user(ldap_user: WritableEntry, dolibarr_us
     if new_group:
         dolibarr_groups = [group for group in dolibarr_groups if group['id'] != new_group['id']] + [new_group]
 
+    if not dolibarr_groups:
+        return
+
     for extra_field in config.LDAP_USERS_EXTRA_FIELDS:
         dolibarr_attrs, ldap_attr = extra_field.split(':')
         dolibarr_attrs = dolibarr_attrs.split('|')