diff --git a/decode-spam-headers.py b/decode-spam-headers.py
index ff290c1..735e93d 100644
--- a/decode-spam-headers.py
+++ b/decode-spam-headers.py
@@ -4387,9 +4387,15 @@ Src: https://www.cisco.com/c/en/us/td/docs/security/esa/esa11-1/user_guide/b_ESA
         m = re.search(r'<?([^<@\s]+)@([^\s]+)>?', value)
         domain = ''
 
+        if not m:
+            return []
+
         if m and len(self.received_path) < 3:
             return []
 
+        if len(m.groups()) < 2:
+            return []
+
         username = m.group(1)
         domain = m.group(2)
         email = f'{username}@{domain}'