--- a/VirtualMailManager/handler.py
+++ b/VirtualMailManager/handler.py
@@ -52,7 +52,7 @@
 
 CFG_FILE = 'vmm.cfg'
 CFG_PATH = '/etc/vmm'
-RE_DOMAIN_SEARCH = """^[a-z0-9-\.]+$"""
+RE_DOMAIN_SEARCH = r"""^[a-z0-9-\.]+$"""
 OTHER_TYPES = {
     TYPE_ACCOUNT: (_('an account'), ACCOUNT_EXISTS),
     TYPE_ALIAS: (_('an alias'), ALIAS_EXISTS),