I have the same issue. I get a “”Your site could not complete a loopback request” in the Site Health area.
I followed roughly the same process as jetxpert to confirm that iThemes Security is causing the problem.
My process:
(1) Deactivated all plugins except iThemes Security (error appeared).
(2) Activated all plugins one by one. Re-ran WP’s Site Health tool after turning on each plugin. Error appeared only when iThemes Security was activated.
(3) Activated all plugins except iThemes Security (error did not appear).
I’m not eager to turn off the “hide backend” feature. Nor do I want to update the code right now for a temporary workaround. I’d rather see a fix from the plugin developer.
