Ah, perhaps you’re using an Android to attempt to connect? The more details you provide, the easier it is to point you in the right direction.
Right now, as indicated in several threads, there’s a bug with connecting an Apple account to Sonos using the Android client. You may want to try a desktop client, or if you can wrangle access to one, an iOS client. Or, just wait until Sonos fixes the issue, but I’m not sure I have any inkling as to how long that might be. Could be tomorrow, could be weeks, they don’t release timing information about upcoming fixes/updates to us in the public.