Error with Mailjet "Failed to authenticate on SMTP"

[Janvier]

I'm trying to configure Mailjet to send transactional emails and with all the settings entered correctly in "Advanced Parameters > E-mail", I get this message: Error: Please check your configuration Failed to authenticate on SMTP server with username "XXXX" using 2 possible authenticators

The username is from Mailjet settings, same for the password. When I save, the password disappears. Is this normal? I use the same email in "Preferences > Store Contacts".
"Use PHP's mail() function (recommended; works in most cases)" works perfectly...

How can I get email with Mailjet to work? The plugin has been installed and configured.

[lesley]

What version of ssl / tls does your server support?

[Janvier]

I'm not certain but I'm on a2hosting. The TLS test on Mailjet was passed with no problem. As it is optional, I've leaved it off for now and I have the same result.

[lesley]

That is strange, that error is usually one that happens because the tsl is the wrong version. Can you send me a link to the module you are using.

[Janvier]

This is the one https://github.com/mailjet/prestashop-mailjet-plugin-apiv3

[lesley]

I think your issue is server related. I just signed up for a mailjet account and tested the module on a test installation and it worked for me. Can you run this on your site and either paste or link the output, https://www.ssllabs.com/ssltest/

[Janvier]

Here are the test results: https://www.ssllabs.com/ssltest/analyze.html?d=www.culturecocktails.com

[lesley]

Hmm strange, it does support the latest versions. Have you tried contacting their support? Since it worked for me, I am thinking there is some other issue somewhere.

[Janvier]

I solved the issue by using port 80