The eReceipt for logged in users will create a different URL key from users that are not logged in.

For example:

http://sample/Components/EReceipt.ashx?key=123 (Generates when User is logged In)

http://sample/Components/EReceipt.ashx?key=5hHdKyRUHKY8GM9Q7GWz (Generates when User is not logged In)