Once you are in the location subaccount:
1. Check what SMTP they are using, if email@example.com is connected in the SMTP integration, the user needs to log in as firstname.lastname@example.org and send the review request.
2. Check if the Email content has any Custom Values and check if they look good.
3. If they use Mailgun, there might be a delay.
Limitation of using SMTP when emails are not sending:
Reviews, Review Requests, and the HighLevel Review Widget: