If you can't open the app, it's possible that something in the installation process may have gone wrong.
Please fully remove the app and then add it again by doing these steps:
Go to wix.com
Make sure you select your site.
Scroll down to Manage Apps.
In the list of apps, click the dots at the end of the Google Reviews App
Remove app.
After removing it add it again https://www.wix.com/app-market/google-reviews-widget
If that doesn't work for you, feel free to contact us for further help.