diff --git a/common/utils.py b/common/utils.py
index 2382f7f..87a5105 100644
--- a/common/utils.py
+++ b/common/utils.py
@@ -125,6 +125,9 @@ def read_target_file(target):
 def get_from_target(target):
     domains = set()
     if isinstance(target, str):
+        if target.endswith('.txt'):
+            logger.log('FETAL', 'Use targets parameter for multiple domain names')
+            exit(1)
         domain = match_main_domain(target)
         if not domain:
             return domains