I am trying to update Reach M+ to the latest version and I get a 404 code "Oops, an error has occured. ReachView is single-page application
Which firmware version is your Reach running? Depending on your current firmware version, there can be different paths to the updater page.
If it’s lower than 26.1, you can access the updater on Reach_IP:5000 in the browser.