Whitelisting / Blacklisting customers gives them the right to use / not use your Arthera On-Chain subscription to pay for their gas fees.
All customers are blacklisted by default. Once a customer makes a successful purchase to one of your subscription plans, the customer will automatically be whitelisted to use your on-chain subscription to pay for his gas fees.
If at any time, the customer's subscription is cancelled (either manually or by a failed payment), the customer will be blacklisted, meaning he will no longer be entitled to use your on-chain subscription to pay for his gas fees. This means that the customer will need to pay gas fees for every transaction he submits while interacting with your dApp.
dApp Operators/Administrators can manually whitelist/blacklist customers from the On-Chain section of the Arthera SMP, in the Whitelisted accounts section.