To troubleshoot this issue, here are some steps you can take:

1. Check the list of compatible file formats your Smart TV supports
2. Check the version of the USB device driver you have installed on your Smart TV
3. Verify the external storage device is NTFS formatted
4. Check that the external storage device is not plugged in too tightly
5. Try an alternate disk with various file formats to test the issue
6. Ensure your external storage device is not manually disconnecting