This guide helps you resolve the email error “The server you are connected to is using a certificate that cannot be verified”.

1. Cause of the error

This error message appears in your software or email client (Microsoft Outlook, Apple Mail, Mozilla Thunderbird, etc.) when the configured server name does not match the SSL certificate that secures the connection.

If you have entered a custom server name (e.g., one composed of the domain name you purchased) such as mail.domaine.xyz while also enabling secure connection (SSL/TLS), your software will detect a conflict because the SSL certificate on the server is only issued for the domaininfomaniak.com.

2. Solution and configuration to apply

To correct this error and ensure a secure connection without certificate warnings, you need to update your email client settings.

Use the official server name

Enter mail.infomaniak.com exclusively as the server name for both receiving and sending emails:

• Incoming server (IMAP or POP): mail.infomaniak.com
• Outgoing server (SMTP): mail.infomaniak.com