Shopify video not playing?

1. Autoplay is being blocked (most common)

Symptom: the video works on desktop but shows a still frame or nothing on mobile.

Cause: every modern browser blocks autoplay when the video has sound. iOS Safari is strictest.

Fix: set the video to muted, and include the playsinline attribute so iOS plays it in place rather than forcing fullscreen. In a theme section, use the muted autoplay option rather than a custom embed. If you need sound, it must start from a user tap — that is not a bug you can work around.

2. The file format is not supported

Symptom: plays in one browser, not another.

Cause: exotic codecs. MOV files straight from an iPhone can use HEVC, which is not universally supported in browsers.

Fix: re-encode to MP4 with H.264 and AAC audio. It is the most compatible combination across browsers and devices, and it is what you should upload by default.

3. The file is too large

Symptom: long blank space, spinner, or it plays only after a delay — worse on mobile data.

Cause: uncompressed video. A phone on a weak connection may never finish buffering, and the visitor leaves first.

Fix: compress before uploading, add a poster image so something paints immediately, and lazy-load anything below the fold. If you are serving raw camera files, this is your problem.

4. Data saver or low power mode

Symptom: fails only for some users, unreproducible for you.

Cause: iOS Low Power Mode and Android/Chrome Data Saver both suppress autoplay.

Fix: you cannot override this, and should not try. Always show a poster image and a visible play control so the video is still obviously there and tappable.

5. A theme or app conflict

Symptom: it broke after installing an app or editing the theme.

Cause: a JavaScript error elsewhere on the page stops the player initialising, or two apps fight over the same element.

Fix: open your browser console (F12) and look for red errors. Disable recently added apps one at a time. Test on a duplicated theme rather than the live one.

6. The embed or URL is wrong

Symptom: blank rectangle where the video should be.

Cause: a shortened or malformed YouTube link, a private or unlisted video, or an iframe stripped by the editor.

Fix: use the full embed code from Share → Embed, confirm the video is public, and paste into the HTML view of the editor rather than the rich-text view.

7. Browser cache or an old theme version

Symptom: it works in incognito but not normally.

Fix: hard refresh (Cmd/Ctrl + Shift + R), test in a private window, and make sure the theme is up to date.

A fast diagnostic order

1. Does it work in a private window? → if yes, cache.
2. Does it work on desktop but not mobile? → autoplay or file size.
3. Does it work in one browser only? → codec.
4. Any console errors? → app or theme conflict.
5. Did it break after an install? → disable that app and retest.

Avoiding the whole category of problem

Most of these come from hand-managing video files and embeds. An app that handles encoding, format, poster images, lazy loading and delivery removes the class of bug rather than the instance — Quinn transcodes on ingest to web-safe formats, compresses up to 20× with an in-house AI encoder, and serves lazily from a CDN, so the video that reaches a phone is already the right format and size.

Questions