handleCaptionsError(target) {
    const playerTrack = this.getTrackById(target.getAttribute('id'));

    playerTrack.isError = true;
    this.removeTrackButton(playerTrack);
    this.checkAllCaptionsLoadedOrError();
  }
Error handler for captions and subtitles. Removs the captions button for erroneous tracks.
@param {Element} target Video track element