Why wasn't my trade processed?

A trade will not be processed if it leaves any of the participants over the maximum roster size or over any position maximums.

It's also possible for trade processing to take a little longer than 24 hours (or 48, depending on league settings). If you mouse-over (or tap on a touch-enabled device) the label Pending, or 24h review you will see the exact time at which the trade is scheduled to complete.