no user exists with this user name in a directory to which you have access

want to add a user from another AAD tenant but that fails with the message 'no user exists with this user name in a directory to which you have access'.

when i try add a user with onMicrosoft.com but it tells no user exists with this user name in a directory to which you have access , i am trying to add user by (user another Microsoft Azure AD directory) and then i try to add the id it puts up a error  can u help me out with this .