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infoWordPress Core•apiREST APIsystem_updateUpdatelooploopbackschedulecron•labelCommon•warningModerate

Loopback request to your site failed

The loopback request error occurs when WordPress tries to call itself via HTTP and fails. This happens because the internal request does not reach wp-cron.php or the REST API.

The failure stops scheduled tasks and blocks health checks. It also prevents automatic updates and can break editor features.

Symptoms

[dashicons-warning]
Site Health warning
The Site Health screen shows “Your site could not complete a loopback request.”
[dashicons-admin-site]
REST API errors
Admin editors display “REST API encountered an error.”
[dashicons-clock]
Scheduled events stop
Cron jobs do not run, automatic updates fail.
[dashicons-editor-code]
Plugin editor blocked
Editor shows “Unable to communicate back with site to check for fatal errors.”

Common Causes

cURL timeout
cURL version is outdated or times out, returning error 28.
PHP resource limits
Low memory_limit or max_execution_time aborts the internal request.
Mismatched site URLs
WP_HOME or WP_SITEURL differs from the actual domain, making the loopback URL unreachable.
Server firewall block
Outbound HTTP from localhost is blocked by firewall, SELinux or ModSecurity.
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