diff --git a/addons/website_slides/i18n/website_slides.pot b/addons/website_slides/i18n/website_slides.pot
index 7a7d7e8202b..8d860372c65 100644
--- a/addons/website_slides/i18n/website_slides.pot
+++ b/addons/website_slides/i18n/website_slides.pot
@@ -5417,7 +5417,8 @@ msgstr ""
 #: code:addons/website_slides/models/slide_slide.py:0
 #, python-format
 msgid ""
-"You cannot mark a slide quiz as completed if you are not among its members."
+"You cannot mark a slide quiz as completed if you are not among its "
+"members or it is unpublished."
 msgstr ""
 
 #. module: website_slides
@@ -5426,7 +5427,7 @@ msgstr ""
 #, python-format
 msgid ""
 "You cannot mark a slide quiz as not completed if you are not among its "
-"members."
+"members or it is unpublished."
 msgstr ""
 
 #. module: website_slides
diff --git a/addons/website_slides/models/slide_slide.py b/addons/website_slides/models/slide_slide.py
index 3c1e7355342..316d01d9617 100644
--- a/addons/website_slides/models/slide_slide.py
+++ b/addons/website_slides/models/slide_slide.py
@@ -912,8 +912,8 @@ class Slide(models.Model):
         """
         if any(not slide.channel_id.is_member or not slide.website_published for slide in self):
             raise UserError(
-                _('You cannot mark a slide quiz as completed if you are not among its members.') if completed
-                else _('You cannot mark a slide quiz as not completed if you are not among its members.')
+                _('You cannot mark a slide quiz as completed if you are not among its members or it is unpublished.') if completed
+                else _('You cannot mark a slide quiz as not completed if you are not among its members or it is unpublished.')
             )
 
         points = 0