diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index a1b91309..3060d18d 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -107,7 +107,7 @@ class ApplicationController < ActionController::Base
   end
 
   def render_csrf_error
-    render_error t('sessions.expired'), :unprocessable_entity
+    render_error t('sessions.expired'), :unprocessable_content
   end
 
   def render_not_authorized
diff --git a/app/controllers/code_ocean/files_controller.rb b/app/controllers/code_ocean/files_controller.rb
index 39ce811d..49111cc2 100644
--- a/app/controllers/code_ocean/files_controller.rb
+++ b/app/controllers/code_ocean/files_controller.rb
@@ -69,7 +69,7 @@ module CodeOcean
             flash[:danger] = t('code_ocean/files.error.filename', name: filename)
             redirect_to(options[:path])
           end
-          format.json { render(json: @object.errors, status: :unprocessable_entity) }
+          format.json { render(json: @object.errors, status: :unprocessable_content) }
         end
       end
     end
diff --git a/app/controllers/comments_controller.rb b/app/controllers/comments_controller.rb
index 79f9c839..ed832359 100644
--- a/app/controllers/comments_controller.rb
+++ b/app/controllers/comments_controller.rb
@@ -45,7 +45,7 @@ class CommentsController < ApplicationController
 
       render :show, status: :created, location: @comment
     else
-      render json: @comment.errors, status: :unprocessable_entity
+      render json: @comment.errors, status: :unprocessable_content
     end
     authorize!
   end
@@ -55,7 +55,7 @@ class CommentsController < ApplicationController
     if @comment.update(comment_params_for_update)
       render :show, status: :ok, location: @comment
     else
-      render json: @comment.errors, status: :unprocessable_entity
+      render json: @comment.errors, status: :unprocessable_content
     end
     authorize!
   end
diff --git a/app/controllers/concerns/common_behavior.rb b/app/controllers/concerns/common_behavior.rb
index 34e05dc5..d4f4cac5 100644
--- a/app/controllers/concerns/common_behavior.rb
+++ b/app/controllers/concerns/common_behavior.rb
@@ -32,7 +32,7 @@ module CommonBehavior
 
   def respond_with_invalid_object(format, options = {})
     format.html { render(options[:template]) }
-    format.json { render(json: @object.errors, status: :unprocessable_entity) }
+    format.json { render(json: @object.errors, status: :unprocessable_content) }
   end
 
   def respond_with_valid_object(format, options = {})
diff --git a/app/controllers/error_template_attributes_controller.rb b/app/controllers/error_template_attributes_controller.rb
index b00b387a..88f736bd 100644
--- a/app/controllers/error_template_attributes_controller.rb
+++ b/app/controllers/error_template_attributes_controller.rb
@@ -47,7 +47,7 @@ class ErrorTemplateAttributesController < ApplicationController
         format.json { render :show, status: :created, location: @error_template_attribute }
       else
         format.html { render :new }
-        format.json { render json: @error_template_attribute.errors, status: :unprocessable_entity }
+        format.json { render json: @error_template_attribute.errors, status: :unprocessable_content }
       end
     end
   end
@@ -64,7 +64,7 @@ class ErrorTemplateAttributesController < ApplicationController
         format.json { render :show, status: :ok, location: @error_template_attribute }
       else
         format.html { render :edit }
-        format.json { render json: @error_template_attribute.errors, status: :unprocessable_entity }
+        format.json { render json: @error_template_attribute.errors, status: :unprocessable_content }
       end
     end
   end
diff --git a/app/controllers/error_templates_controller.rb b/app/controllers/error_templates_controller.rb
index 6b89e680..c8c376df 100644
--- a/app/controllers/error_templates_controller.rb
+++ b/app/controllers/error_templates_controller.rb
@@ -44,7 +44,7 @@ class ErrorTemplatesController < ApplicationController
         format.json { render :show, status: :created, location: @error_template }
       else
         format.html { render :new }
-        format.json { render json: @error_template.errors, status: :unprocessable_entity }
+        format.json { render json: @error_template.errors, status: :unprocessable_content }
       end
     end
   end
@@ -59,7 +59,7 @@ class ErrorTemplatesController < ApplicationController
         format.json { render :show, status: :ok, location: @error_template }
       else
         format.html { render :edit }
-        format.json { render json: @error_template.errors, status: :unprocessable_entity }
+        format.json { render json: @error_template.errors, status: :unprocessable_content }
       end
     end
   end
diff --git a/app/controllers/events_controller.rb b/app/controllers/events_controller.rb
index 16ba0d63..e353537c 100644
--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb
@@ -11,8 +11,8 @@ class EventsController < ApplicationController
         format.html { head :created }
         format.json { head :created }
       else
-        format.html { head :unprocessable_entity }
-        format.json { head :unprocessable_entity }
+        format.html { head :unprocessable_content }
+        format.json { head :unprocessable_content }
       end
     end
   end
diff --git a/app/controllers/file_templates_controller.rb b/app/controllers/file_templates_controller.rb
index 224860e0..f88a3726 100644
--- a/app/controllers/file_templates_controller.rb
+++ b/app/controllers/file_templates_controller.rb
@@ -52,7 +52,7 @@ class FileTemplatesController < ApplicationController
         format.json { render :show, status: :created, location: @file_template }
       else
         format.html { render :new }
-        format.json { render json: @file_template.errors, status: :unprocessable_entity }
+        format.json { render json: @file_template.errors, status: :unprocessable_content }
       end
     end
   end
@@ -67,7 +67,7 @@ class FileTemplatesController < ApplicationController
         format.json { render :show, status: :ok, location: @file_template }
       else
         format.html { render :edit }
-        format.json { render json: @file_template.errors, status: :unprocessable_entity }
+        format.json { render json: @file_template.errors, status: :unprocessable_content }
       end
     end
   end
diff --git a/app/controllers/request_for_comments_controller.rb b/app/controllers/request_for_comments_controller.rb
index b92de462..9df21cb8 100644
--- a/app/controllers/request_for_comments_controller.rb
+++ b/app/controllers/request_for_comments_controller.rb
@@ -123,7 +123,7 @@ class RequestForCommentsController < ApplicationController
       if @request_for_comment.save
         format.json { render :show, status: :ok, location: @request_for_comment }
       else
-        format.json { render json: @request_for_comment.errors, status: :unprocessable_entity }
+        format.json { render json: @request_for_comment.errors, status: :unprocessable_content }
       end
     end
   end
@@ -140,7 +140,7 @@ class RequestForCommentsController < ApplicationController
       if @request_for_comment.save
         format.json { render :show, status: :ok, location: @request_for_comment }
       else
-        format.json { render json: @request_for_comment.errors, status: :unprocessable_entity }
+        format.json { render json: @request_for_comment.errors, status: :unprocessable_content }
       end
     end
   end
@@ -183,7 +183,7 @@ class RequestForCommentsController < ApplicationController
         end
       else
         format.html { render :new }
-        format.json { render json: @request_for_comment.errors, status: :unprocessable_entity }
+        format.json { render json: @request_for_comment.errors, status: :unprocessable_content }
       end
     end
     authorize!
diff --git a/app/controllers/subscriptions_controller.rb b/app/controllers/subscriptions_controller.rb
index 65575884..dd8cd29e 100644
--- a/app/controllers/subscriptions_controller.rb
+++ b/app/controllers/subscriptions_controller.rb
@@ -13,7 +13,7 @@ class SubscriptionsController < ApplicationController
       if @subscription.save
         format.json { render json: @subscription, status: :created }
       else
-        format.json { render json: @subscription.errors, status: :unprocessable_entity }
+        format.json { render json: @subscription.errors, status: :unprocessable_content }
       end
     end
     authorize!
diff --git a/spec/controllers/code_ocean/files_controller_spec.rb b/spec/controllers/code_ocean/files_controller_spec.rb
index 3285f7fc..9ba96965 100644
--- a/spec/controllers/code_ocean/files_controller_spec.rb
+++ b/spec/controllers/code_ocean/files_controller_spec.rb
@@ -58,7 +58,7 @@ RSpec.describe CodeOcean::FilesController do
 
       expect_assigns(file: CodeOcean::File)
       expect_json
-      expect_http_status(:unprocessable_entity)
+      expect_http_status(:unprocessable_content)
     end
   end
 
diff --git a/spec/controllers/events_controller_spec.rb b/spec/controllers/events_controller_spec.rb
index e2f3da99..5f3b75e6 100644
--- a/spec/controllers/events_controller_spec.rb
+++ b/spec/controllers/events_controller_spec.rb
@@ -29,13 +29,13 @@ RSpec.describe EventsController do
       before { post :create, params: {event: {exercise_id: 847_482}} }
 
       expect_assigns(event: Event)
-      expect_http_status(:unprocessable_entity)
+      expect_http_status(:unprocessable_content)
     end
 
     context 'with no event' do
       before { post :create }
 
-      expect_http_status(:unprocessable_entity)
+      expect_http_status(:unprocessable_content)
     end
   end
 end
diff --git a/spec/controllers/submissions_controller_spec.rb b/spec/controllers/submissions_controller_spec.rb
index 1d346dca..f929062e 100644
--- a/spec/controllers/submissions_controller_spec.rb
+++ b/spec/controllers/submissions_controller_spec.rb
@@ -36,7 +36,7 @@ RSpec.describe SubmissionsController do
 
         expect_assigns(submission: Submission)
         expect_json
-        expect_http_status(:unprocessable_entity)
+        expect_http_status(:unprocessable_content)
       end
     end