diff --git a/actionmailbox/test/dummy/public/400.html b/actionmailbox/test/dummy/public/400.html
index f55b448339640..3a93ebc085848 100644
--- a/actionmailbox/test/dummy/public/400.html
+++ b/actionmailbox/test/dummy/public/400.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <title>The request parameters are malformed (400)</title>
+  <title>The request is malformed and cannot be processed (400)</title>
   <meta name="viewport" content="width=device-width,initial-scale=1">
   <style>
   .rails-default-error-page {
@@ -58,8 +58,8 @@
   <!-- This file lives in public/400.html -->
   <div class="dialog">
     <div>
-      <h1>The request parameters are malformed.</h1>
-      <p>Maybe the URL is malformed or required form data is missing.</p>
+      <h1>The server cannot process the request due to a client error.</h1>
+      <p>Please check the request and try again.</p>
     </div>
     <p>If you are the application owner check the logs for more information.</p>
   </div>
diff --git a/actiontext/test/dummy/public/400.html b/actiontext/test/dummy/public/400.html
index f55b448339640..3a93ebc085848 100644
--- a/actiontext/test/dummy/public/400.html
+++ b/actiontext/test/dummy/public/400.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <title>The request parameters are malformed (400)</title>
+  <title>The request is malformed and cannot be processed (400)</title>
   <meta name="viewport" content="width=device-width,initial-scale=1">
   <style>
   .rails-default-error-page {
@@ -58,8 +58,8 @@
   <!-- This file lives in public/400.html -->
   <div class="dialog">
     <div>
-      <h1>The request parameters are malformed.</h1>
-      <p>Maybe the URL is malformed or required form data is missing.</p>
+      <h1>The server cannot process the request due to a client error.</h1>
+      <p>Please check the request and try again.</p>
     </div>
     <p>If you are the application owner check the logs for more information.</p>
   </div>
diff --git a/activestorage/test/dummy/public/400.html b/activestorage/test/dummy/public/400.html
index f55b448339640..3a93ebc085848 100644
--- a/activestorage/test/dummy/public/400.html
+++ b/activestorage/test/dummy/public/400.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <title>The request parameters are malformed (400)</title>
+  <title>The request is malformed and cannot be processed (400)</title>
   <meta name="viewport" content="width=device-width,initial-scale=1">
   <style>
   .rails-default-error-page {
@@ -58,8 +58,8 @@
   <!-- This file lives in public/400.html -->
   <div class="dialog">
     <div>
-      <h1>The request parameters are malformed.</h1>
-      <p>Maybe the URL is malformed or required form data is missing.</p>
+      <h1>The server cannot process the request due to a client error.</h1>
+      <p>Please check the request and try again.</p>
     </div>
     <p>If you are the application owner check the logs for more information.</p>
   </div>
diff --git a/railties/lib/rails/generators/rails/app/templates/public/400.html b/railties/lib/rails/generators/rails/app/templates/public/400.html
index f55b448339640..3a93ebc085848 100644
--- a/railties/lib/rails/generators/rails/app/templates/public/400.html
+++ b/railties/lib/rails/generators/rails/app/templates/public/400.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <html>
 <head>
-  <title>The request parameters are malformed (400)</title>
+  <title>The request is malformed and cannot be processed (400)</title>
   <meta name="viewport" content="width=device-width,initial-scale=1">
   <style>
   .rails-default-error-page {
@@ -58,8 +58,8 @@
   <!-- This file lives in public/400.html -->
   <div class="dialog">
     <div>
-      <h1>The request parameters are malformed.</h1>
-      <p>Maybe the URL is malformed or required form data is missing.</p>
+      <h1>The server cannot process the request due to a client error.</h1>
+      <p>Please check the request and try again.</p>
     </div>
     <p>If you are the application owner check the logs for more information.</p>
   </div>
