@kzk972 I'm having the same problem on Windows, so I used your link and changed /mac/ to /win/ and that URL worked, but the version didn't solve my problem. The outcome was the same.
IF anyone has a solution to this, it would be VERY appreciated. The Sync settings say that open tabs are synced, but I cannot find any way to view my phone tabs on laptop or laptop tabs on phone. Flow is the only way to send links back and forth.
Opera on my laptop just redirects to this, with nowhere to enter the code from my phone.