Check the actual viewing option
A detailed poster is not a video-quality label. Look at the quality offered for the particular movie on your chosen service. HD, 1080p and 4K availability can differ between versions, plans and devices.
Audio and subtitles belong together
Check both the spoken language and the subtitle language. For a dubbed edition, ordinary subtitles and captions that match the dubbed dialogue may be separate options. Test a short scene before settling into the film.
When the picture keeps stopping
Try the player’s automatic quality setting or a lower available resolution. If other downloads are using the connection, pause those first. Return to a higher setting once playback is stable.