Identify three possible text sources
First inspect whether Windows Live captions is active. Then check the player’s subtitle menu. Finally consider whether the text is part of the picture itself, such as an old recording with permanently visible subtitles. A caption style setting cannot restyle pixels that already belong to the video image.
A useful visual clue is whether the text disappears when the player’s caption track is turned off. Make that comparison with the viewer’s agreement and restore the needed captions immediately afterward. Do not leave somebody without access merely to demonstrate which layer is active.
Change the controlling setting
For a player-generated subtitle track, use that player’s documented appearance controls where available. For Windows-generated captions, use the system caption controls. If the text is embedded, inspect supported zoom or display choices carefully without cropping information needed for understanding.
Compare a light and a dark scene, not just the style preview. Text that looks clear against a sample background can disappear against real footage. Keep the original configuration in a note so a less useful experiment can be reversed quickly.
Describe the limitation precisely
If the app supplies no appearance controls, report that fact to its accessibility support with the platform and caption type. Avoid changing the service password or reinstalling codecs because the font differs from a Windows preview. Those actions do not establish control of the caption layer.
A helpful example image shows the readability problem while hiding account details. State whether the issue is size, contrast, position or obstruction. Font styling does not correct a missing language track or inaccurate transcription, so keep those concerns separate in the support request.