With the Thunderbolt, USB or Dante versions of the Aurora(n), it is critical that the sample rate that the Aurora(n) is operating at matches the sample rate of the SD card material. When there is a discrepancy, the sample rate will appear below the TAKE name in the main display in Red.
When the unit is connected to the computer, you generally can not change the sample rate from the front panel CLOCK SETUP button. Instead, you need to change it from the computer. If you have audio software open, you should be able to change the sample rate within the audio software application. If not, you can change it from the Sound Section of Windows Control Panel in Windows OS, or from the Utilities > Audio MIDI Setup page in MacOS. With Dante, you will need to change the sample rate from the DEVICE INFO page of the Dante Controller software
After setting the sample rate to match the rate of the TAKE, playback should be possible.