This guide helps resolve an email error of type "the recipient was rejected by the server, server response 550 5.7.1 relaying denied" or "Proper authentication required".

Resolve a Relaying denied error

Check that the parameter "My server requires authentication" is enabled in the settings of your outgoing SMTP server in the email software you are using. You will find this parameter in the software you are using under a section type "Additional settings" or "Advanced configuration" under “Outgoing SMTP server”.

After correcting this, delete/move the pending messages and try with a new message.

Click here to access the Infomaniak configuration tool (online service https://config.infomaniak.com) — log in if necessary to your Infomaniak account on the Organization where your email address is managed.

Refer to this other guide for error resolution.

If the error mentions "IP name possibly forged" instead, it will be necessary to check the situation with the person responsible for your IP address.