What are soft bounces and hard bounces?

The term "bounce" refers to a message that has failed to be delivered and resulted in an error message. There are two types of bounces: 

  • soft bounces (ex: the recipient's server is unavailable or their inbox is full)
  • hard bounces (ex: non-existent address or blocked email address).

Note: SendinBlue automatically blacklists contacts that result in hard bounces.