diff --git a/spec/file_caching_test.js b/spec/file_caching_test.js
index 8c50df879b3e73e321b08426e68faddc6284daa8..82aa8a3c5b1d9c3d47fd3d225f7e1cdb849b489c 100644
--- a/spec/file_caching_test.js
+++ b/spec/file_caching_test.js
@@ -292,7 +292,7 @@ describe('File caching service', function () {
     app = await injectApp()
 
     const response1 = await app.inject({ url: '/example.js' })
-    expect(response1.statusCode).to.equal(404)
+    expect(response1.statusCode).to.equal(503)
 
     const response2 = await app.inject({ url: '/example.js' })
     expect(response2.statusCode).to.equal(200)
diff --git a/src/errors.js b/src/errors.js
index b931f0cbcb753e917a53ea4f26c2ef34741130b8..1d7073f04d47ae6da5d6e0d8b307f4b160d0447b 100644
--- a/src/errors.js
+++ b/src/errors.js
@@ -14,7 +14,7 @@ export class VersionMismatchError extends Error {}
  */
 export function isVersionMismatchError (err) {
   const errors = err instanceof AggregateError ? err.errors : [err]
-  return errors.reduce((memo, error) => memo && error instanceof VersionMismatchError, true)
+  return errors.some(error => error instanceof VersionMismatchError)
 }
 
 /**
@@ -24,5 +24,5 @@ export function isVersionMismatchError (err) {
  */
 export function isNotFoundError (err) {
   const errors = err instanceof AggregateError ? err.errors : [err]
-  return errors.reduce((memo, error) => memo && error instanceof NotFoundError, true)
+  return errors.some(error => error instanceof NotFoundError)
 }
diff --git a/src/routes/serve-files.js b/src/routes/serve-files.js
index 641a910d9471afccea1d7e3fc5a6175a18ec91ef..4a56c66e9553d7939a4a4eec68a0d9c747cd77a5 100644
--- a/src/routes/serve-files.js
+++ b/src/routes/serve-files.js
@@ -9,11 +9,10 @@ export default async function serveFilePlugin (fastify, options) {
 
       const path = url === '/' ? '/index.html' : url
       const { body, headers } = await getFile({ version, path })
-
       reply.headers(headers)
       reply.send(body)
     } catch (err) {
-      if (isNotFoundError(err) || isVersionMismatchError(err)) throw fastify.httpErrors.createError(404, `File "${req.urlData('path')}" does not exist.`)
+      if (isNotFoundError(err) || isVersionMismatchError(err)) throw fastify.httpErrors.createError(404, `File "${req.urlData('path')}" does not exist.`, err)
       throw fastify.httpErrors.createError(err.statusCode || 500, err)
     }
   })