diff --git a/package.json b/package.json
index ac4a516..a5822de 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@lambda-feedback-segp-sandbox/ef-test-server",
-  "version": "0.3.0",
+  "version": "0.4.0",
   "main": "dist/index.js",
   "scripts": {
     "build": "yarn tsc",
diff --git a/src/handler.ts b/src/handler.ts
index e2a04a4..4623185 100644
--- a/src/handler.ts
+++ b/src/handler.ts
@@ -13,11 +13,22 @@ export function parseRequestBody(body: unknown): {
   return { url, evaluationFunctionRequestData }
 }
 
-export async function handleRawRequest(body: unknown): Promise<object | null> {
+export enum HandlerError {
+  ParseFailed,
+  ForwardingFailed,
+}
+
+export async function handleRawRequest(
+  body: unknown,
+): Promise<object | HandlerError> {
   const parseResult = parseRequestBody(body)
-  if (parseResult == null) return null
+  if (parseResult == null) return HandlerError.ParseFailed
 
   const { url, evaluationFunctionRequestData } = parseResult
-  const response = await axios.post(url, evaluationFunctionRequestData)
-  return response.data
+  try {
+    const response = await axios.post(url, evaluationFunctionRequestData)
+    return response.data
+  } catch (_) {
+    return HandlerError.ForwardingFailed
+  }
 }
diff --git a/src/index.ts b/src/index.ts
index 1e5cc30..993800c 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -2,7 +2,7 @@ import cors from 'cors'
 import express from 'express'
 import dotenv from 'dotenv'
 
-import { handleRawRequest } from './handler'
+import { HandlerError, handleRawRequest } from './handler'
 
 dotenv.config()
 
@@ -14,15 +14,21 @@ app.use(express.json())
 app.post('/', async (req, res) => {
   console.log(`[INFO] Received POST request:`, req.body)
   const responseData = await handleRawRequest(req.body)
-  if (responseData == null) {
-    console.log('[WARN] Invalid request received and ignored.')
-    res.status(400).send()
-  } else {
-    console.log(
-      '[INFO] Received response from evaluation function:',
-      responseData,
-    )
-    res.send(responseData)
+  switch (responseData) {
+    case HandlerError.ParseFailed:
+      console.log('[WARN] Invalid request received and ignored.')
+      res.status(400).send()
+      break
+    case HandlerError.ForwardingFailed:
+      console.log('[WARN] Failed to forward request to evaluation function.')
+      res.status(400).send()
+      break
+    default:
+      console.log(
+        '[INFO] Received response from evaluation function:',
+        responseData,
+      )
+      res.send(responseData)
   }
 })