Avoiding blocks
Fix blank or blocked screenshots caused by bot detection, Cloudflare, or 403s.
The most common support issue by far: the screenshot comes back blank, shows a "checking your browser" page, or returns a 403 / Access Denied. The site has detected automated traffic and blocked it.
Why it happens
Bot-protection services (Cloudflare, DataDome, PerimeterX) and simple 403 rules detect headless browsers and known datacenter IP ranges, then serve a challenge or block page instead of the real content.
Fix
Try these in order:
use_stealth— apply anti-detection measures so the browser looks like a normal one.proxy— route the render through your own proxy ([user:pass@]address:port, Ultra plan). Oruse_proxyto use the proxy configured on your project.
{ "url": "https://example.com", "use_stealth": true, "use_proxy": true}If that doesn't work
- Use a residential proxy rather than a datacenter one — it's the single biggest factor for tough sites.
- Set a realistic
user_agent. - Block the scripts doing the detection with
block_urls. - If the page renders but looks broken rather than blocked, set
engine_versiontolatest.
Urlbox does not solve CAPTCHAs. Avoiding detection in the first place — stealth plus a good proxy — is far more reliable than trying to defeat a challenge after it appears.
You get a different page than the one you asked for
Sometimes the render succeeds and looks perfectly fine — it just isn't the page you requested. A product page comes back as the homepage, for instance.
Urlbox renders leave from our own servers, which are US-based by default (it's why tz reports a US timezone). Some sites vary what they serve by visitor location, and a few redirect visitors they detect as being in the US somewhere else entirely — often unintentionally.
To check, open the same URL yourself from a US IP address in a private window. If the site does redirect, routing the render through a proxy changes where the request appears to come from.