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WordPress REST API Image Upload Returns 405? Check Your Hostinger CDN

· 4 min read
CCLEE
CCLEE

While building a WooCommerce product import tool for a client, POST /wp-json/wp/v2/media would succeed for the first few images, then suddenly return 405 Not Allowed for all subsequent requests.

TL;DR​

Hostinger CDN (hcdn) blocks POST /wp-json/wp/v2/media requests by default. The response headers server: hcdn and x-hcdn-request-id are the smoking gun. Disable CDN or contact Hostinger support to whitelist /wp-json/* POST requests.

The Problem​

Uploading images to WordPress Media Library via REST API:

curl -X POST 'https://example.com/wp-json/wp/v2/media' \
  -u 'user:app_password' \
  -H 'Content-Disposition: attachment; filename="product-01.jpg"' \
  -H 'Content-Type: image/jpeg' \
  --data-binary @image.jpg

The first 2-4 images return 201 Created, then all subsequent requests fail with:

<html>
<head><title>405 Not Allowed</title></head>
<body>
<center><h1>405 Not Allowed</h1></center>
<hr><center>nginx</center>
</body>
</html>

This "partial success" pattern is misleading — it looks like rate limiting, but the real cause is entirely different.

Root Cause​

Using curl -v to inspect the full response headers revealed:

< HTTP/2 405
< server: hcdn
< x-hcdn-request-id: cfc5ad1198938cd9f1e02ce71ed0ae61-kul-edge1

Key findings:

  • server: hcdn — This is Hostinger's custom CDN (hcdn), not the origin nginx server
  • x-hcdn-request-id — CDN edge node ID (kul-edge1 = Kuala Lumpur), confirming the request was blocked at the CDN layer before reaching WordPress

Hostinger CDN's default security rules block POST requests to /wp-json/wp/v2/media. The initial successes were likely due to CDN rule cold-start or cache misses.

Solution​

Option 1: Disable CDN (Quick Fix)​

Go to Hostinger hPanel → Website → CDN → Disable.

This takes effect immediately but removes CDN acceleration. Suitable for staging environments or emergency fixes.

Submit a support ticket requesting to whitelist POST requests to /wp-json/*. Hostinger's Manage panel currently doesn't offer custom CDN rule configuration — you must go through support.

Option 3: Add Retry Logic in Code (Defensive Measure)​

Even with correct CDN configuration, retry logic handles occasional CDN throttling:

import time
import random

def upload_image(url, image_bytes, filename, auth, max_retries=3):
    for attempt in range(max_retries):
        resp = httpx.post(
            url,
            content=image_bytes,
            headers={
                "Content-Disposition": f'attachment; filename="{filename}"',
                "Content-Type": "image/jpeg",
            },
            auth=auth,
            timeout=30,
        )
        if resp.status_code != 405:
            return resp
        delay = 3 * (attempt + 1) + random.uniform(0, 2)
        time.sleep(delay)
    resp.raise_for_status()

Troubleshooting Journey​

This issue led down several dead ends. Here's the full排查 path for reference:

HypothesisActionResult
WP plugin blockingDisabled Speed Optimizer / Auto Upload ImagesStill 405, ruled out
Rate limitingAdded 2-5s delay between uploads + retryStill 405, ruled out
REST API disabledGET /wp-json/wp/v2/settingsReturned normally, ruled out
Auth credentialsWC Test ConnectionSucceeded, ruled out
CDN blockingcurl -v to inspect response headersserver: hcdn confirmed CDN blocking

The turning point was using curl -v and spotting server: hcdn — only then did we realize the requests never reached WordPress.

Important Notes

  • After disabling CDN, DNS cache may take a few minutes to refresh — don't retry immediately
  • If your site is on Hostinger and uses REST API for batch operations, test CDN behavior before going live
  • WooCommerce WC API (/wc/v3/products) uses different authentication (Consumer Key) and is typically unaffected; this mainly impacts WP REST API (/wp-json/wp/v2/*) write operations

FAQ​

Why does WordPress REST API image upload return 405 Not Allowed?​

Check the server field in response headers. If it shows hcdn (Hostinger CDN) or another CDN identifier, the request is being blocked at the CDN layer before reaching WordPress. Disable the CDN or contact your hosting provider to whitelist the endpoint.

How to tell if 405 comes from CDN or WordPress?​

Use curl -v and inspect response headers: a server value of hcdn, cloudflare, or other CDN identifiers indicates CDN-level blocking; a server value of nginx/apache with X-WP-* or X-RateLimit-* headers means the request reached WordPress.

Encountered this issue while building a WooCommerce product import tool for a client. If you're also developing with Hostinger + WordPress and running into REST API issues, reach out.

CCLEE

Independent developer, 24 years in e-commerce, focused on grounding AI in real business scenarios.

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