These files are identical length (time-wise). One is 24 bit the other is 16 bit. UE4 doesn't support 24 bit sound files.
Unable to import a sound file shorter than 1 second in length. The two sound files attached are the same sound, but one has been extended to at least 1 second long and successfully imports.
1. Download the Sound Files attached.
2. Attempt to Import both sounds into any project.
3. Observe error message and failure to import the shorter sound.
Head over to the existing Questions & Answers thread and let us know what's up.