Have you encountered the error 4.7.8: Error: authentication failed ? You should probably check your credentials.
Please check that the credentials used are the API KEY (username) and SECRET KEY (password) as shown on your SMTP Settings page. Do not use the email address and password that you use to log into your Mailjet account; this will not work.
If you still experience an error, check the encryption method used: SSL on port 465; TLS for port 587.
If you have any questions about using SMTP relay, please contact our Support Team.
If you still experience an error, check the encryption method used: SSL on port 465; TLS for port 587.
If you have any questions about using SMTP relay, please contact our Support Team.