Sites not being created properly with multisite and Pro sites

I have installed pro sites and multisite on my website

Neither adding a site from the frontend or the backend works.

If I add it from the frontend, it doesn't even appear in the backend under the "sites" list. And if I try to click the activation link in the email, that doesn't work either.

If I add it from the backend, it appears in the sites list but does not work in the browser.

Any help would be appreciated.