diff --git a/app/utils.py b/app/utils.py
index 56d711117..3f8a3b599 100644
--- a/app/utils.py
+++ b/app/utils.py
@@ -610,8 +610,8 @@ LETTER_VALIDATION_MESSAGES = {
             '<br>Save a new copy of your file and try again.'
         ),
         'summary': (
-            'Letters must be 10 pages or less. <br>'
-            'This letter is {page_count} pages long.'
+            'Validation failed because Notify cannot read this PDF.<br>'
+            'Save a new copy of your file and try again.'
         ),
     },
     'address-is-empty': {
diff --git a/tests/app/test_utils.py b/tests/app/test_utils.py
index ee177e6b3..a8dc0755b 100644
--- a/tests/app/test_utils.py
+++ b/tests/app/test_utils.py
@@ -469,6 +469,19 @@ def test_get_letter_validation_error_for_unknown_error():
             'Letters must be 10 pages or less.'
         ),
     ),
+    (
+        'unable-to-read-the-file',
+        [2],
+        'There’s a problem with your file',
+        (
+            'Notify cannot read this PDF.'
+            'Save a new copy of your file and try again.'
+        ),
+        (
+            'Validation failed because Notify cannot read this PDF.'
+            'Save a new copy of your file and try again.'
+        ),
+    ),
 ])
 def test_get_letter_validation_error_for_known_errors(
     client_request,