Widget isn’t showing at all
Six causes, in the order they are worth checking. Most cases are the first three.
Widget not showing on Shopify
On Shopify the widget is usually missing because the Custom Liquid block was added to a template the page does not use, or the change was previewed rather than saved..
The short answer
On Shopify the widget is usually missing because the Custom Liquid block was added to a template the page does not use, or the change was previewed rather than saved.
Both are visible in the theme editor within a minute.
Check in this order
The template — a block on the Default product template will not appear on a page using a different product template. Check which template the page uses.
Saved, not previewed — changes in Customize need saving. Previewing shows the change to you and nobody else.
The right theme — it is easy to edit a duplicated theme rather than the live one. Confirm you are editing the published theme.
Cache — Shopify and any CDN in front of it may serve the old page. Hard-reload.
App blocks
If installed through the App Store rather than as Custom Liquid, the block appears in the theme editor under Apps. It still needs adding to a template — installing the app alone does not place anything.
Still missing
Send support the page URL and the widget installation code. A password-protected store needs the password too, or there is nothing to look at.
Questions
Other common problems
Adding a review source
Most sources connect by pasting a link to your public profile on that platform.
Error while collecting reviews
Two error messages can appear when you add a source.
New reviews haven’t appeared yet
New reviews appear in the widget on their own, but not instantly.