diff --git a/src/FetchWorkerTool.worker.js b/src/FetchWorkerTool.worker.js
index 43965250..be87df0d 100644
--- a/src/FetchWorkerTool.worker.js
+++ b/src/FetchWorkerTool.worker.js
@@ -49,7 +49,10 @@ const onMessage = ({data: job}) => {
     jobsActive++;
 
     fetch(job.url, job.options)
-        .then(response => response.arrayBuffer())
+        .then(result => {
+            if (result.ok) return result.arrayBuffer();
+            return Promise.reject(result.status);
+        })
         .then(buffer => complete.push({id: job.id, buffer}))
         .catch(error => complete.push({id: job.id, error}))
         .then(() => jobsActive--);