diff --git a/mail/anonymisers.py b/mail/anonymisers.py
index 37d446bd..05f79869 100644
--- a/mail/anonymisers.py
+++ b/mail/anonymisers.py
@@ -63,6 +63,9 @@ def sanitize_product_line(line):
 
 def sanitize_edi_data(lines):
 
+    if not lines:
+        return f"{today()}: empty edi data"
+
     if "fileHeader" not in lines and "fileTrailer" not in lines:
         return f"{today()}: invalid edi data"