HTTP 429 / 454 / 455 Blocked

• HTTP 429
• HTTP 454
• HTTP 455
• Services whitelisted
  • Bots impersonating approved services
  • Requirements for whitelist addition

Simply.com uses an advanced protection system (Web Application Firewall) to prevent and block attacks, abuse and exploitation of vulnerabilities in our customers' websites.

¶HTTP 429

When you encounter this error code, the web server performs an automatic security check of your browser before allowing you to continue. The check is to protect the site from bots and automated attacks that could overload the server or attempt to exploit vulnerabilities.

All normal browsers can complete this check without problems and will subsequently receive an HTTP 200 response code.
In most cases the check happens in the background, and a regular browser with JavaScript and cookies enabled gets through in a few seconds without you noticing. When the check has passed, you can browse the site freely for a while before it may be performed again.

You may see the message “Checking your browser” for a number of reasons, for example:

• The site is currently receiving an unusually high number of requests or is under attack.
• The visit comes from an IP address that has a poor “reputation” and is known for attacks. You can look up the IP address at www.simply.com/rbl/.
• A known crawler that has made too many requests in a short period.
• The error code may also originate from the site’s own code and protection (outside our control).

If you get stuck at the check, try reloading the page, refreshing your browser or accessing the site from another device or network connection.

The error code tells the visitor that they should/can try again later.

¶HTTP 454

This response code can occur if:

• You are using a very old browser that lacks the features modern web relies on.
• You are pretending to be a very old browser that lacks the features modern web relies on.

All normal browsers can complete this check without problems and will subsequently receive an HTTP 200 response code.

If you own the site and notice that legitimate visitors, integrations or devices are being affected, first contact the owner of the integration and ask them to investigate the issue.

¶HTTP 455

This response code can occur if:

• The individual request is blocked due to a firewall rule.
• An AI agent that does not use a custom user‑agent, or uses a user‑agent also employed by botnets.

You can see the precise reason for the block by reviewing the logs for your product. This is done under “Webserver logs” → “Webserver Application Firewall” in our Control Panel.
Based on the reason you will likely be able to resolve the block.

¶Services whitelisted

Well‑known third‑party services such as Googlebot, OpenAI, Anthropic, Bing, LinkedIn, Jetpack, PayPal, Facebook, ManageWP, etc. are whitelisted in our security filter.

We do not whitelist security services, as our security filter itself is a security element – and removing it to scan security therefore does not make much sense.

¶Bots impersonating approved services

If you investigate blocks, note that many bots impersonate these known services in an attempt to get through the security filter. Therefore always check whether it is actually an approved service that is being blocked (based on IP address).

¶Requirements for whitelist addition

In general our WAF behaves properly towards legitimate requests, i.e. requests that comply with common rules. If you wish to whitelist a known third‑party service, we can offer this provided there is a public and maintained URL containing a list of the used IP addresses.