When you download either the developer_viewer.ipa, or distribution_viewer.zip, for a built-in single edition app, the process fails. You receive the error "Sign in failed, please try again."
One or more of your built-in folio's articles contain upper-ASCII or other special characters, such as accented characters, ampersands, or parentheses.
Remove any accented characters, such as é, ü, å, and other special characters such as & and ) from the article names in your folio, and the folio name.
Adobe is actively pursuing additional solutions to this problem and hopes to address it in a future release.