diff --git a/src/lib/oa-rpde.js b/src/lib/oa-rpde.js
index a42cfaf..7d6fe58 100644
--- a/src/lib/oa-rpde.js
+++ b/src/lib/oa-rpde.js
@@ -29,6 +29,9 @@ class OpenActiveRpde {
         try {
           log(`Fetching ${nextURL}`);
           let res = await fetch(nextURL);
+          if (!res.ok) {
+            throw res.status + " - " + res.statusText;
+          }
 
           let activitiesJson = await res.json();
 
diff --git a/src/lib/stage-both.js b/src/lib/stage-both.js
index 5934543..1db8c87 100644
--- a/src/lib/stage-both.js
+++ b/src/lib/stage-both.js
@@ -19,6 +19,10 @@ async function processBothStages() {
   await Utils.loadActivitiesJSONIntoCache();
 
   let res = await fetch(Settings.registryURL);
+  if (!res.ok) {
+    throw res.status + " - " + res.statusText;
+  }
+
   let registryJson = await res.json();
 
   for (const publisherKey in registryJson.data) {
diff --git a/src/lib/stage1.js b/src/lib/stage1.js
index 05fa31e..a5fde28 100644
--- a/src/lib/stage1.js
+++ b/src/lib/stage1.js
@@ -18,6 +18,9 @@ async function processStage1() {
   }
 
   let res = await fetch(Settings.registryURL);
+  if (!res.ok) {
+    throw res.status + " - " + res.statusText;
+  }
   let registryJson = await res.json();
 
   for (const publisherKey in registryJson.data) {
diff --git a/src/lib/stage2.js b/src/lib/stage2.js
index 435818d..f0d7a09 100644
--- a/src/lib/stage2.js
+++ b/src/lib/stage2.js
@@ -20,6 +20,9 @@ async function processStage2() {
   await Utils.loadActivitiesJSONIntoCache();
 
   let res = await fetch(Settings.registryURL);
+  if (!res.ok) {
+    throw res.status + " - " + res.statusText;
+  }
   let registryJson = await res.json();
 
   for (const publisherKey in registryJson.data) {
diff --git a/src/lib/utils.js b/src/lib/utils.js
index 20435c5..5d00160 100644
--- a/src/lib/utils.js
+++ b/src/lib/utils.js
@@ -51,7 +51,9 @@ class Utils {
 
 
     const res = await fetch(Settings.activityListJSONLD);
-    // TODO  detect non 200 responses
+    if (!res.ok) {
+      throw res.status + " - " + res.statusText;
+    }
     const activitiesData =  await res.json();