wp-activate.php not found

Hi there! new user here. I’m trying to add new users (authors) to a blog and apparently the activation link in the email doesn’t work. It just brings a page with the following message:

The requested URL /wp-activate.php was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

the link that gets sent in the email is as follows:

https://shslive.com/rabner/wp-activate.php?key=c1160aab408e739e

I’ve been looking around to find a fix but can’t seem to find one. I’ve deactivated all plugins and that doesn’t fix things either. However, I find that if I add them without sending a confirmation email, then it works just fine.

Suggestions?