When importing your Google reviews, not all businesses show up in the Google business search. This is usually because your Business Profile doesn't have an address added to it.
In this case, click on the 'Not found' heading below the search to reveal the Google OAuth connection button. Here you can log in with your Google account (that has access to the Business Profile) to import your reviews this way.
After you connect to Google, the reviews will be automatically imported once a day to your account. If you have Autopublish on in the import section, you'll even get the reviews directly to your widgets without any intervention.