diff --git a/handlers/errorHandlers.js b/handlers/errorHandlers.js
index 48465e4..9fc3ce0 100644
--- a/handlers/errorHandlers.js
+++ b/handlers/errorHandlers.js
@@ -7,6 +7,8 @@
 
 exports.catchErrors = (fn) => {
   return function (req, res, next) {
-    return fn(req, res, next).catch(next)
+    return fn(req, res, next).catch((e) => {
+      next(e)
+    })
   }
 }
diff --git a/routes/courses.js b/routes/courses.js
index 6552e6b..bf77d18 100644
--- a/routes/courses.js
+++ b/routes/courses.js
@@ -36,14 +36,13 @@ router.get('/:slug', catchErrors(async function (req, res, next) {
   const lessonIndex = lessons.findIndex((lesson) => lesson.fields.slug === req.params.lslug)
   const lesson = lessons[lessonIndex]
   const cookie = req.cookies.visitedLessons
-  let visitedLessons = cookie ||  []
+  let visitedLessons = cookie || []
   visitedLessons.push(course.sys.id)
   visitedLessons = [...new Set(visitedLessons)]
   res.cookie('visitedLessons', visitedLessons, { maxAge: 900000, httpOnly: true })
   res.render('course', {title: course.fields.title, course, lesson, lessons, lessonIndex, visitedLessons})
 }))
 
-
 /* GET course lesson detail. */
 router.get('/:cslug/lessons/:lslug', catchErrors(async function (req, res, next) {
   let course = await getCourse(req.params.cslug, req.query.locale, req.query.api)
diff --git a/services/contentful.js b/services/contentful.js
index 312573c..e176eea 100644
--- a/services/contentful.js
+++ b/services/contentful.js
@@ -23,13 +23,13 @@ exports.initClient = (options) => {
   })
 }
 
-exports.getCourses = (locale = 'en-US', api = `cda`) => {
+exports.getCourses = assert((locale = 'en-US', api = `cda`) => {
   // to get all the courses we request all the entries
   // with the content_type `course` from Contentful
   const client = api === 'cda' ? cdaClient : cpaClient
   return client.getEntries({content_type: 'course', locale, include: 10})
     .then((response) => response.items)
-}
+}, 'Course')
 
 exports.getLandingPage = (locale = 'en-US', api = `cda`) => {
   // our Home page is fully configureable via Contentful
@@ -39,26 +39,22 @@ exports.getLandingPage = (locale = 'en-US', api = `cda`) => {
     .then((response) => response.items[0])
 }
 
-exports.getCourse = (slug, locale = 'en-US', api = `cda`) => {
+exports.getCourse = assert((slug, locale = 'en-US', api = `cda`) => {
   // the SDK supports link resolution only when you call the collection endpoints
   // That's why we are using getEntries with a query instead of getEntry(entryId)
   // make sure to specify the content_type whenever you want to perform a query
   const client = api === 'cda' ? cdaClient : cpaClient
   return client.getEntries({content_type: 'course', 'fields.slug': slug, locale, include: 10})
     .then((response) => response.items[0])
-}
+}, 'Course')
 
-exports.getLessons = (courseId, locale = 'en-US', api = `cda`) => {
-  // TODO
-}
-
-exports.getCategories = (locale = 'en-US', api = `cda`) => {
+exports.getCategories = assert((locale = 'en-US', api = `cda`) => {
   const client = api === 'cda' ? cdaClient : cpaClient
   return client.getEntries({content_type: 'category', locale})
     .then((response) => response.items)
-}
+}, 'Course')
 
-exports.getCoursesByCategory = (category, locale = 'en-US', api = `cda`) => {
+exports.getCoursesByCategory = assert((category, locale = 'en-US', api = `cda`) => {
   const client = api === 'cda' ? cdaClient : cpaClient
   return client.getEntries({
     content_type: 'course',
@@ -67,5 +63,18 @@ exports.getCoursesByCategory = (category, locale = 'en-US', api = `cda`) => {
     include: 10
   })
     .then((response) => response.items)
-}
+}, 'Category')
 
+function assert (fn, context) {
+  return function (req, res, next) {
+    return fn(req, res, next)
+    .then((data) => {
+      if (!data) {
+        var err = new Error(`${context} Not Found`)
+        err.status = 404
+        throw err
+      }
+      return data
+    })
+  }
+}
diff --git a/views/error.pug b/views/error.pug
index 1c6e394..cceb8e7 100644
--- a/views/error.pug
+++ b/views/error.pug
@@ -2,6 +2,15 @@ extends layout
 
 block content
   .layout-centered
-    h1= message
-    h2= error.status
-    pre #{error.stack}
+    .error
+      h1 Oops Something went wrong (#{error.status})
+      h2 Try:
+      ul
+        li Check if the content model has changed
+        li Check the selection has content in draft or published state (for Preview or Delivery)
+        li Check if there's any content for this locale
+        li Verify credentials are correct and up to date
+        li Check the stack trace below
+
+      h2 Stack trace
+      pre.error__stack-trace #{error.stack}