Non-delivery & Blocked Addresses

Automatic blocking. If an email is not delivered because it was dropped, deferred, bounced, reported as spam or unsubscribed, the recipient address is blocked. Continuing to send to such addresses would harm your domain reputation.
Spam reports. If a recipient marked your email as spam, they must manually mark it as Not Spam themselves.
Unsubscribes. An unsubscribed recipient can be unblocked only after Gupshup receives an email from the business point of contact confirming the address should receive emails again.