diff --git a/src/repository/groupRepository.py b/src/repository/groupRepository.py
index 43832e0..004683f 100644
--- a/src/repository/groupRepository.py
+++ b/src/repository/groupRepository.py
@@ -50,7 +50,7 @@ class GroupRepository:
                 Group(chat_id, group_name, group[self.count])
             )
 
-        if not groups:
+        if not result:
             raise NotFoundException
 
         return result
diff --git a/src/validator/groupNameValidator.py b/src/validator/groupNameValidator.py
index 3eca5e4..4c89902 100644
--- a/src/validator/groupNameValidator.py
+++ b/src/validator/groupNameValidator.py
@@ -4,13 +4,14 @@ from exception.invalidArgumentException import InvalidArgumentException
 
 
 class GroupNameValidator:
+    MAX_GROUP_NAME_LENGTH: int = 20
 
     @staticmethod
     def validate(group: str) -> None:
         group = group.lower()
 
-        if len(group) > 0 and not re.match(r"^[A-Za-z]+$", group):
-            raise InvalidArgumentException(re.escape('Group name must contain only letters.'))
+        if len(group) > 0 and not re.match('^\w+$', group):
+            raise InvalidArgumentException(re.escape('Special characters are not allowed.'))
 
-        if len(group) > 20:
-            raise InvalidArgumentException(re.escape(f'Group name length can not be greater than 20.'))
+        if len(group) > GroupNameValidator.MAX_GROUP_NAME_LENGTH:
+            raise InvalidArgumentException(re.escape(f'Group name length can not be greater than {GroupNameValidator.MAX_GROUP_NAME_LENGTH}.'))