WebVTT is a timed-text format used with web media. It can carry cues and presentation information that a compatible player displays alongside video. Seeing a VTT file does not guarantee a particular language, translation quality or accessibility completeness; those depend on the actual caption content.
Understand the separate track
A text track can be enabled, disabled and styled where the player supports those controls. This differs from captions burned into the video pixels. The browser or application must retrieve and parse the track successfully, so video playback can work while the text fails because of a separate delivery or formatting problem.
Inspect the visible behaviour
If captions never appear, check that the intended track is selected and try another available language. If only some lines are misplaced, cue positioning or player handling may be involved. A complete absence, a timing offset and unreadable text are different symptoms and should be described separately.
Use support information safely
For a website you manage, a developer can inspect the caption request and formatting using appropriate tools. As a viewer, report the title, app, language and time without posting private media URLs. Do not assume changing the video resolution will repair a text track that is missing or malformed.