CheckView automatically detects when security plugins, firewalls, or bot protection services are blocking test execution. Instead of a cryptic failure, you’ll see a clear error message identifying the blocker and how to resolve it.
Blocker detection runs automatically during:
When a blocker is detected, a red error card appears on the test results or setup error page with:

CheckView detects 14 security and firewall services:
CheckView also detects two non-security issues that prevent testing:
The resolution depends on which service is blocking CheckView. For the following services, we have dedicated step-by-step guides:
For all other blockers (Sucuri, ModSecurity, Imunify360, LiteSpeed, BitNinja, ConfigServer Firewall, CHEQ), you’ll need to whitelist CheckView’s IP addresses in your hosting or security service’s control panel. See Whitelisting CheckView IPs and Bypassing Security Plugin Blocks for general guidance.
You can also use the CheckView IP addresses page to get the current list of IPs to whitelist, including a Cloudflare-compatible CSV download.
These services have their own whitelisting documentation, though they are not auto-detected by blocker detection: