Nice Score is a rating from 1 to 5 that is internally tracked by Vtiger CRM.
Nice Score increases automatically from 1 to 2 if your initial campaigns do not exceed the thresholds of spam complaints, unsubscribes, or bounces. As the Nice Score increases, the number of email credits you can use also increases.What are the thresholds for spam complaints, unsubscribes, and bounces
A high number of spam complaints, unsubscribes, or bounces indicate that most recipients have not subscribed to receive your emails. By sending unsolicited emails, you might turn away your customers.