diff --git a/mail_inline_css/models/mail_template.py b/mail_inline_css/models/mail_template.py
index a7e5d9032..c45e00811 100644
--- a/mail_inline_css/models/mail_template.py
+++ b/mail_inline_css/models/mail_template.py
@@ -28,6 +28,8 @@ class MailTemplate(models.Model):
         return result
 
     def _premailer_apply_transform(self, data_html):
+        if not data_html:
+            return data_html
         premailer = Premailer(html=data_html, **self._get_premailer_options())
         return premailer.transform()