Contact Form 7 forwards each submission to Akismet for spam analysis. Akismet validates the request through its REST endpoint. When the request fails, CF7 displays a generic error banner.
The failure can stem from an invalid or missing API key. It can also arise when the server cannot reach the Akismet endpoint due to firewall rules, DNS problems, or outdated TLS support. A mismatched field tag sends malformed data, which the API rejects.
Rate‑limit exhaustion produces an explicit error response from Akismet. Conflicting plugins or theme code that alter HTTP headers may also break the request. PHP environments lacking cURL or the required OpenSSL version cannot complete the HTTPS call.