diff --git a/server.ts b/server.ts
index 3e10677a8b1..6f61b8f20f9 100644
--- a/server.ts
+++ b/server.ts
@@ -443,6 +443,10 @@ function saveToCache(req, page: any) {
     const key = getCacheKey(req);
     // Avoid caching "/reload/[random]" paths (these are hard refreshes after logout)
     if (key.startsWith('/reload')) { return; }
+    // Avoid caching non-successful responses (status code different from 2XX). Without this, the
+    // rendered 404 not-found page gets stored in the cache and is later replayed via res.send()
+    // as HTTP 200 - turning a correct 404 into a soft-404. (matches dtq-dev cache behaviour)
+    if (hasNotSucceeded(req.res.statusCode)) { return; }
 
     // If bot cache is enabled, save it to that cache if it doesn't exist or is expired
     // (NOTE: has() will return false if page is expired in cache)
@@ -459,6 +463,15 @@ function saveToCache(req, page: any) {
   }
 }
 
+/**
+ * Check if status code is different from 2XX
+ * @param statusCode HTTP status code of the current response
+ */
+function hasNotSucceeded(statusCode) {
+  const rgx = new RegExp(/^20+/);
+  return !rgx.test(statusCode);
+}
+
 /**
  * Whether a user is authenticated or not
  */