Error while sending mails


I have an issue with some outgoing mails.
They are not send, and an adress “Administrateur système” reply with the following mail :
"Erreur serveur : ‘451 Sender rate limit exceeded, domain temporary disabled’ "
I don’t understand why i have this error.
Maybe it’s a hour/day sending limit ?
Below, this is a snap of the error :

Thanks for helping.



Have you sent many mails recently? In this case it is possible that your accound has been temporary limited.
There is a limitation on the STMP service that limits the number of emails that can be sent from our servers:

You can contact our support team by ticket if you still have an issue with sending emails.




Thank you for your answer.
It’s right, we have some hours where we sending a lot of emails, and it’s when the system is blocking.

I’m going to open an ticket on the support.