Account pending

Hi support team,
All my account is set an active but when configuring the options for the first newsletter they are blocked due to following message :

L’envoi a été mis en pause en raison d’un problème technique avec MailPoet: MailPoet Sending Service has been temporarily suspended for your site due to degraded email deliverability. Please contact our support team to resolve the issue.

Could you please help me activate it.
Thanks