If your Fire TV is not showing the DVR menu, it's possible the Fire TV stick is not registered to the same account as the Fire TV Recast.

To check what account the Fire TV Stick is registered to, go to Settings > My Account.  From here, it will show the name of the Account.

To check what account the Fire TV Recast is connected to, load the Fire TV app on your phone or tablet.  Select Settings and up top it will show the account.

If you need to connect the Fire TV to a new Amazon account, select  Settings > My Account > Deregister, then after it is de-registered, you can re-register it to the correct Amazon account.

If that's not the problem, you can try re-pairing the Recast to the Fire TV.  To do this, go to Settings > Live TV > Sync Sources > Fire TV Recast > Unpair this Fire TV Recast > OK

Next, you will want to re-pair it by selecting Pair a Fire TV Recast, and select the name of your Fire TV Recast.  It will take 30 seconds or so to pair.