Scan troubleshooting: why a scan gets blocked, fails, or times out

A reference for every scan error SuperSchema can show, what each one usually means, and how to fix it. Most failures come down to bot protection, a firewall, or a slow response, and the fix is almost always allowing SuperSchemaBot or trying another public page.

A scan reads your public pages the way a search engine or AI crawler would. When a scan gets blocked, fails, or times out, it is almost always because something stopped SuperSchema from reaching those pages, not because your site is broken. Your site can load perfectly in a normal browser and still block automated readers like ours. This page lists every error the scan can show, what each one usually means, and how to fix it.

Tip The single most common fix is to allow our crawler, SuperSchemaBot, in your firewall or bot-protection rules and make sure robots.txt does not disallow it. If you only read one section, read "How to allow SuperSchemaBot" below.

The two most common blocks #

The majority of failed scans land on one of these two states. Both are access blocks, and neither is retryable on its own; the fix is to let SuperSchema through or try a different public page.

Site Security Challenge: Shown as: "This page loads in a normal browser, but Cloudflare or another security tool blocked SuperSchema from scanning it." Likely cause: Cloudflare, a firewall, or bot protection served a challenge our scanner could not pass. Fix: "Ask your site admin to allow SuperSchema, lower bot protection for this URL, or try another public page from the same site."
Website Access Blocked: Shown when SuperSchema could read 0 public pages: "SuperSchema could not read any public pages from this site. The website may still load normally in your browser, but a firewall, Cloudflare rule, or bot-protection setting can block scanners like ours." Fix: same as above. Ask your admin to allow SuperSchema, lower bot protection for the URL, or try another public page from the same site.

Note When a site security challenge is detected, SuperSchema also reassures you that "this usually means the website is online and SuperSchema is not broken." Its security settings are blocking automated scanners, so the scan cannot read the page until that blocker is adjusted.

Every scan error and how to fix it #

Beyond the two access blocks above, the scan can surface a handful of connection and page-level errors. Each one comes with its own set of tips in the app. Use this table as the symptom-to-cause-to-fix reference:

Error	Likely cause	What to do
Site Security Challenge	Cloudflare, a firewall, or bot protection blocked the scanner even though the page loads in a browser.	Allow SuperSchema, lower bot protection for the URL, or try another public page from the same site.
Website Access Blocked	A firewall, Cloudflare rule, or bot-protection setting stopped the scan from reading any public pages.	Allow SuperSchema, lower bot protection for the URL, or try a different public page.
DNS error	The domain could not be found: a typo, a domain that is offline, or a DNS problem.	Double-check the URL for typos (such as "wwww"), confirm the domain is spelled correctly, and try visiting it in your browser to verify it works.
SSL error	The site’s security certificate is expired or misconfigured.	Ask the website owner about the certificate, or try again later since certificate issues are sometimes temporary.
Connection refused / reset	The server is down or restarting, or it is blocking automated access.	Try again in a few minutes. If it keeps happening, the site likely has firewall rules blocking scanners.
Website timeout / page timeout	The site took too long to respond, often from high traffic or blocking cloud-based access.	Try again later, or try a different page on the same site.
Redirect loop	The site has a redirect configuration problem that never resolves.	This is a website-side issue. Contact the site owner, or try a more specific URL path.
Page not found	The page was moved or deleted, or the path is wrong or case-sensitive.	Try the homepage and navigate to the content, and check the URL path.
Access denied / login required	The page needs login or special access; SuperSchema can only read public pages.	Try the homepage or another public page. Ask the site admin to allow SuperSchema if the page is meant to be public.

How to allow SuperSchemaBot #

SuperSchema identifies itself with a clear user agent and respects robots.txt. To let a scan through, allow that user agent in both places that can block it: your bot-protection or firewall rules, and your robots.txt file.

text

Mozilla/5.0 (compatible; SuperSchemaBot/1.0; +https://superschema.ai/bot)

In Cloudflare, your WAF, or your security plugin, add an allow rule for the SuperSchemaBot user agent (or lower bot protection for the specific URL you want scanned).
In your robots.txt, make sure no rule disallows SuperSchemaBot for the pages you want read.
Re-run the scan. If it now reads your pages, you can claim the report as usual.

text

User-agent: SuperSchemaBot
Allow: /

Note The scan is read-only. It only requests your public pages and never logs in, changes your content, or modifies your settings. Allowing it does not expose anything a normal search-engine crawler could not already see.

When to just try another page #

If you cannot change firewall or robots.txt rules right now (for example, someone else manages the site), the fastest workaround is to scan a different public page from the same site. A public blog post or a standard content page is often readable even when the homepage sits behind a stricter challenge. The error screens themselves suggest this: "try another public page from the same site."

Tip Pages that require login, sit behind a paywall, or return a login prompt cannot be scanned. Point the scan at a page anyone can open in a browser without signing in.

Timeouts and long-running scans #

Most scans finish quickly, but larger or slower sites take longer. The scan checks for progress every 3 seconds and keeps waiting up to 10 minutes before it gives up. If it runs past that, you will see: "This scan is taking longer than expected. Please refresh this page or start another scan." Refreshing or starting a fresh scan usually clears a one-off slow response.

Note If you open a scan link that is missing its access token, you will see "This scan link is missing its access token." Start the scan again from the homepage so a valid link is generated, rather than editing the URL by hand.

Scan limits #

Free scans are rate-limited to protect site owners from repeated automated requests. If you hit a limit, wait and try again later:

Limit	Value
Scans per IP address, per hour	10
Concurrent scans per IP address	2
Scans per domain, per day	5
How long a scan preview link stays valid	24 hours

Tip If you have already scanned a domain and just want to keep working, claim the report you already have instead of re-scanning. Claiming attaches the existing result to your account without spending another scan against the daily domain limit.