Voicemail Drops require mp3 or wav audio files. This article shows how to properly convert your audio voicemail file to properly utilize Voicemail Drops.
What you will need
Step 1: Download Audacity
Visit the Audacity website
Start your Download - it's free!
Step 2: How to properly convert audio files
Drag and drop your audio file into Audacity
On the bottom left, lower the project rate down to 8000
Tracks → Resample... → 8000 → OK
File → Export Audio → Name the File in the Save As → Format: Other uncompressed files → Options → Header: WAV → Encoding: U-Law → OK → Save → OK