The incident has been resolved on our provider's side, there is no more impact on our services.

Our engineers have identified the root source of the problem.
It is related to our network provider.
https://status.cloud.google.com/incident/cloud-networking/18019

Mailjet public website, user interface and all APIs are fully functional although some users are still experiencing temporary access problems. We sincerely apologise for the inconvenience. Should you need any additional support, we are here to help. You can speak with our support team here: https://app.mailjet.com/support/ticket

We are continuing to investigate this issue.

Some of our users may have difficulty accessing our public website, user interface and our Send API 3.1. Our technical team is rapidly investigating the situation. We will update you here with new information shortly.