Things that catch people out

A redirect that does not seem to fire. Use Test an address at the top of the Redirects screen — it says what the site actually does with that address. If it says the redirect is working and your browser disagrees, your browser is remembering an earlier permanent redirect: try a private window, or your phone.

A redirect that works for you and not for your visitors. A page cache answers before WordPress, and so before any redirect, and it never answers you while you are signed in. So adding, changing, switching on or off, or deleting a redirect clears that address from NimbleCache, WP Rocket, LiteSpeed Cache, W3 Total Cache and WP Super Cache, whichever are installed, once the save is done. WP Fastest Cache, SiteGround Speed Optimizer, Breeze, WP-Optimize and Cloudflare (through Cloudflare's own plugin, which is what clears APO) cannot clear one address, so they are emptied instead. A section rule empties every cache, because no list names every page under it, and so does changing more than a hundred redirects at once, such as importing a file. LiteSpeed Cache is asked for its pages only: its CSS and JS files, the object cache and Cloudflare stay as they are. On a network, WP Super Cache is emptied only for the site whose redirects changed, never for every site. A cache WordPress cannot reach, such as your host's own, keeps its copy until it expires or you empty it there. Another cache can listen for the trrd_purge_url action, which names each address, and for trrd_purge_caches, which asks for everything.

A redirect to a page that itself redirects. It works, but each hop costs the visitor a round trip. Once the weekly check has marked it, its row has a button naming the final address, and one press points it there (see Checking your own redirects).

An address that is part of WordPress. /wp-admin, /wp-login.php, /wp-json and the rest are refused, because a rule over one of them locks you out of your own site at the moment you find out.

Nothing appearing on Broken links. Either nothing is breaking — which is the answer you want — or watching is switched off in Settings, in which case the screen says so at the top.

An address you expected on Broken links is not there. It may be on Never list these addresses, perhaps under a section line ending in *. The line above the table says how many lines that list holds, and links to it.

An address you removed keeps coming back. Remove from the list only deletes the row. Use Never list this again for one you never want to see.