A If “Failed to retrieve your information” error is shown even if you input a correct ID and a password, please check that the My Channel of the Youtube account has been created.
You can check the My Channel from “My Channel” which is shown by clicking the account which is shown in upper right.
Please create the My Channel if you haven’t created the My Channel yet.
Please change the window to the PC mode by tapping “PC” button which is shown at upper left before you operate these on the iPad or the iPhone.