- Plesk for Linux
- Plesk Onyx for Linux
Cannot send an email from Airmail or Apple Mail client for a domain with Let's Encrypt certificate enabled. "Impossible to send your email" error message appeared.
Apple mail clients have SSL support enabled as default. Postfix mail server on the Plesk server uses certificate assigned to
domain name. When mail client verifies the certificate, it founds a mismatch in domain name specified in mail account
and cannot validate it. This behavior is expected.
1. To avoid that specify server.example.com as SMTP outgoing mail server in Apple mail client settings.
2. Use multi-domain server as the one for Postfix mail server
3. Use non-SSL connection in the mail client.
https://discussions.apple.com/thread/4164964?start=0&tstart=0 - how to turn off SSL in Mac mail client