i created a new folio and paid close attention to how I was adding
here's what i did:
• i added a new folio
• added 4 different vertical articles
this worked fine
• I added my horizontal articles
from here. no horizontal articles showed
up on my adobe content viewer, on my ipad.
they all showed up fine however
in my browser-based Folio builder.
am I adding articles incorrectly?
It sounds like you're adding your horizontal layouts as different articles. For each article in a dual-orientation folio, you should have two layouts -- one horizontal and one vertical. Is that what you're doing? If you have four horizontal articles and four vertical articles, your folio won't preview on the folio level either on the desktop or on the iPad. But if you have four articles each with two layouts, your folio should preview.