You may encounter times where your Z2 won't send a video. An error message like, "Attachment limit reached" may pop up. Often, the cause of this error is that the video file is too large for an MMS message. Thankfully, the Z2 has two ways to make sure your videos will be able to send in a message.
First, you can change the settings in the camera app:
In addition, if you record video from inside the messages app, it will automatically make it compatible with an MMS message.