Webmail does not redirect to HTTPS
Your clients should always use https to connect to webmail, to avoid being vulnerable to attacks. A good method to ensure this is the case is to redirect from non-https to https.
To enable the https redirect got to the hosting settings of your domain and enable “Permanent SEO-safe 301 redirect from HTTP to HTTPS”.
No DNS entry for the webmail url
Plesk Premium Email must be able to resolve the webmail url to the same system it is running on.
Can’t connect to webmail using HTTPS
This indicates that you system does not support https. Ensure your system is properly secured with a suitable certificate (e.g. from Let’s Encrypt).
The domain is configured to use Horde instead of Roundcube
Plesk Premium Email relies on Roundcube being configured for the domain. If this is not the case the webmail will not be available.
To fix this go to the “Mail Settings” of this domain and select “Roundcube” as webmail.
The domain is configured to use Roundcube instead of Plesk Premium Email
Plesk Premium Email needs to be selected as webmail even if the permission is set. This is normally done automatically when changing the permission.
To fix this go to the “Mail Settings” of this domain and select “Plesk Premium Email” as webmail.
Preferred domain redirects are not supported and will break various features
Preferred domain redirects (e.g. “example.com” -> “www.example.com”) are currently not supported and will break various features, including seafile integration, activesync and collabora integration.
To disable the redirect got to the hosting settings of your domain and enable select “None” as “Preferred domain”.