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4. Troubleshooting Common Integration Issues
 
 Troubleshooting Latest      10 min read  

# Troubleshooting Common Integration Issues

  A  admin  April 15, 2026  

 

 

 

 

 

 

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 ## Problem: 401 Unauthorized on Every Request

**Most common causes:**

1. **Token expired** — Access tokens expire after 3,600 seconds. Implement token refresh logic
2. **Wrong environment** — Using a sandbox token against the production endpoint or vice versa
3. **Whitespace in token** — Ensure there are no leading/trailing spaces in the Authorization header value

\# Debug: Check token expiry  
import jwt  
payload = jwt.decode(token, options={"verify\_signature": False})  
print(payload\["exp"\]) # Compare with current Unix timestamp

## Problem: CORS Errors in Browser

Aelix APIs do not support browser-based (CORS) calls for security reasons. API credentials must never be exposed to browsers. Use a backend proxy instead:

// Your backend  
app.get('/api/accounts', async (req, res) => {  
 const data = await aelixClient.banking.accounts.list();  
 res.json(data);  
});

// Your frontend calls YOUR backend, not Aelix directly  
const accounts = await fetch('/api/accounts').then(r => r.json());

## Problem: 422 Unprocessable Entity

Check the details array in the error response — it specifies exactly which fields failed validation:

{  
 "error": {  
 "code": "VALIDATION\_FAILED",  
 "details": \[  
 { "field": "amount", "issue": "must be a positive integer" },  
 { "field": "currency", "issue": "must be an ISO 4217 code" }  
 \]  
 }  
}

## Problem: Slow Response Times

1. Check the X-Response-Time header — if low, the latency is in your network, not the API
2. Enable connection keep-alive in your HTTP client to avoid TCP handshake overhead
3. Co-locate your application servers in the same region as the Aelix API (eu-west-1)
4. Use the fields query parameter to request only the fields your app needs

## Problem: Webhook Delivery Not Received

1. Verify your endpoint is publicly accessible over HTTPS (not localhost)
2. Check the **Webhook Delivery Log** in the portal for response codes and retry history
3. Ensure your endpoint responds with HTTP 200 within 5 seconds
4. Confirm the webhook secret matches — a signature mismatch causes your endpoint to reject delivery



 

 

 

 ### Tags

Tags

[Error Handling](/taxonomy/term/43)