sending not possible

Hello, from France
Before sending a newsletter I wanted to check by sending it to me by email, but it is impossible. I have an error message:

The email could not be sent due to a technical issue with MailPoet: The email could not be sent: The MailPoet sending service has been temporarily suspended for your site due to a deterioration in the deliverability of e-mails. Please contact our support team to resolve this issue.
The extension is up to date.
It’s been a while since I last sent. Is it for this reason? How to understand what is going on.
Thanks for your help.`