Email service providers have a limit on the size of outgoing emails. It is possible that you were trying to send a recording that is too large for them to handle it.

At the time of writing, the limits are:

• Gmail: 25 MB
• Outlook or Hotmail: 10 MB
• Yahoo! Mail: 25 MB
• AOL: 25 MB

To share recordings that are larger than 25 MB, you can upload the recordings to cloud storage services like DropBox, Google Drive or SkyDrive and send the sharing link by email.