Why does my Google review QR code go to a sign-in page instead of the review form?

Google requires users to log in to leave a review in order to prevent fake reviews, this is why your customers may have seen the sign in screen. If the user is already logged into Google on their phone they will already be signed in and will directly leave you a review.

Android phones are able to post reviews without any issue. However, if the user is not already signed into a Google account on their device, Google will prompt them to sign in or create one before submitting the review.

Yes, anyone with a Google account can leave a Google review, regardless of their email address.

…One thing that may help is linking your QR code to directly open the Google Maps app. If your customer is logged in already on the Google Maps app, they won't need to log in.