Below are some steps you can follow to solve this issue:

1. Check if the mandatory subtitle settings are enabled:
   Go to the Audio Settings and check if the caption settings are turned On.
2. Search for the right subtitle track:
   Go to the audio or video settings and manually select the subtitle that is meant to appear.
3. Check if the subtitle format is compatible with your Smart TV:
   Similar to video files, subtitles may also be encoded in a format that is not supported by your device.
4. Re-Download the correct subtitle:
   Download the subtitle file from the same source you used for the video or audio file.