Envoyer status checks failing

Seems there is no Envoyer support contact(!) so asking this here...

Our site's status page is just a simple route which returns the text 'OK', and tests successfully in a browser.

But Envoyer is currently reporting 404s from all three test locations when using this site. It has worked up until today, and I haven't changed anything. Other sites in Envoyer that are hosted on the same server are still reporting status good.

Does anyone know if there is an issue with Envoyer's status check, or a way to contact Envoyer support?

regards David