diff --git a/instruct/handlers.py b/instruct/handlers.py
index 6edc7cd..b029855 100644
--- a/instruct/handlers.py
+++ b/instruct/handlers.py
@@ -34,22 +34,32 @@ def _get_user_cn(user_id: str) -> str:
     try:
         # Заменяем tcs.sibcem.ru на sibcem.ru
         search_id = user_id.replace("@tcs.sibcem.ru", "@sibcem.ru")
-        short_username = search_id.split("@")[0] if "@" in search_id else search_id
+        short_username = search_id.split("@")[0] if "@" in search_id else user_id
         safe_id = escape_filter_chars(search_id)
         safe_short = escape_filter_chars(short_username)
 
+        logger.info(f"AD lookup: user_id={user_id}, search_id={search_id}, short={short_username}")
+
         server = Server(AD_SERVER, get_info=ALL)
         conn = Connection(server, user=AD_USER, password=AD_PASSWORD, auto_bind=True)
-        search_filter = (
-            f"(&(objectClass=user)(|"
-            f"(mail={safe_id})"
-            f"(userPrincipalName={safe_id})"
-            f"(sAMAccountName={safe_short}))"
-            f"))"
-        )
-        conn.search(AD_BASE, search_filter, attributes=["cn", "sAMAccountName"])
-        if conn.entries:
-            return str(conn.entries[0].cn)
+
+        # Пробуем несколько фильтров
+        filters = [
+            f"(mail={safe_id})",
+            f"(userPrincipalName={safe_id})",
+            f"(sAMAccountName={safe_short})",
+        ]
+        for filt in filters:
+            conn.search(AD_BASE, f"(&(objectClass=user)({filt}))", attributes=["cn", "sAMAccountName", "mail"])
+            if conn.entries:
+                entry = conn.entries[0]
+                cn = str(entry.cn)
+                mail = str(entry.mail) if 'mail' in entry else "N/A"
+                sam = str(entry.sAMAccountName) if 'sAMAccountName' in entry else "N/A"
+                logger.info(f"AD found: cn={cn}, mail={mail}, sam={sam}")
+                return cn
+
+        logger.warning(f"AD not found for user_id={user_id}, search_id={search_id}, short={short_username}")
     except Exception as e:
         logger.error(f"Ошибка получения CN из AD для {user_id}: {e}")
     return user_id  # fallback — используем user_id как CN