courier tracking link in woocommerce order emails goes nowhere

Check the carrier itself didn't change its tracking URL. Couriers redesign their sites and the old link format quietly goes to the homepage, so a template that worked last year breaks without you touching anything. Paste one tracking number into the carrier's site by hand, then compare that URL with the one your email builds.

Are you using a tracking plugin or did you paste the link into the order note yourself? If it's a plugin, it builds the link from a URL template per carrier plus the tracking number. When the link lands on the carrier's homepage or an error page, it's almost always one of these: - the carrier picked on the order isn't the one that actually shipped it - a custom carrier was added with a URL template that's missing the tracking number placeholder - the tracking number has spaces or a stray character copied in Open the link from a test email and look at the URL itself. If the number isn't in it, it's the template.