diff --git a/packages/gatsby/cache-dir/loader.js b/packages/gatsby/cache-dir/loader.js
index ec1a387065e67..8dc50983320b6 100644
--- a/packages/gatsby/cache-dir/loader.js
+++ b/packages/gatsby/cache-dir/loader.js
@@ -887,7 +887,16 @@ export class ProdLoader extends BaseLoader {
         }
         // check if html file exist using HEAD request:
         // if it does we should navigate to it instead of showing 404
-        return doFetch(rawPath, `HEAD`).then(req => {
+
+        // OLD CODE
+
+        // return doFetch(rawPath, `HEAD`).then(req => {
+
+        // NEW FIX: include pathPrefix
+        const prefixedPath = __PATH_PREFIX__
+          ? __PATH_PREFIX__ + rawPath
+          : rawPath
+        return doFetch(prefixedPath, `HEAD`).then(req => {
           if (req.status === 200) {
             // page (.html file) actually exist (or we asked for 404 )
             // returning page resources status as errored to trigger