Adding a review source
Most sources connect by pasting a link to your public profile on that platform.
Google Customer Reviews aren’t supported
Google Customer Reviews — the Merchant Center survey programme at customerreviews.google.com — is not a supported source and cannot be collected automatically..
The short answer
Google Customer Reviews — the Merchant Center survey programme at customerreviews.google.com — is not a supported source and cannot be collected automatically.
Google Business Profile reviews, which is what most people mean, are fully supported.
Which one you have
If your reviews came from a post-purchase survey Google emailed your buyers, and they feed a seller rating in Shopping ads, that is Google Customer Reviews. If they are the reviews on your Maps listing, that is a Business Profile and it works.
The full difference is explained here — it is a 6,600-a-month confusion and worth two minutes.
The workaround
Add them by hand, one at a time, in the All-in-One app. Tedious for a large set, fine for a handful of strong ones.
If you want it supported
It is on the wishlist and votes are counted.
Questions
Other common problems
Widget isn’t showing at all
Six causes, in the order they are worth checking. Most cases are the first three.
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.