Sorry! I've found the problem!
Was the bad TabId, I've some difficoult to find it on DNN 7.2 version.
For find the right TabId go on Page management and after selected the checkout page you can see on the url something like this: http://yourwebsite/Admin/Pages#P&261 In this example the TabId is 261.
The strange thing is that with the bad TabId I was redirect from Paypal to other portal and not on the home page of the right web site!
Was the bad TabId, I've some difficoult to find it on DNN 7.2 version.
For find the right TabId go on Page management and after selected the checkout page you can see on the url something like this: http://yourwebsite/Admin/Pages#P&261 In this example the TabId is 261.
The strange thing is that with the bad TabId I was redirect from Paypal to other portal and not on the home page of the right web site!