Hi Chad,
thanks. But it seems that the user (defined by the email address "otheruser@mail.com") should have an account at Wolfram Research.
At least - the corresponding login windows pops up if the URL is activated at the other computer.
With
Permissions -> {All -> {"Read", "Interact", "Evaluate"}}
I can open the notebook on the other computer without login but without interactive possibilities either.
Is it possible that a user without any connection to WR can open and use interactively a cloud notebook?