We can't use SSL in Thunderbird, but it's working in Outlook. When I test the account settings, it says: "Thunderbird failed to find the settings for your email account." I've looked it up on Google and found an older article saying that SSL is not working for Thunderbird vs. 38 (I have a newer version anyways, but maybe it's the same problem). They say this: Essentially the problem lies with the configuration of the DHE key in the mail server itself. Not your email client, but your email host server. The length of a DHE key must be 1023 bits or greater to work properly. However many mail server installation defaults set this key to 768 bits. When the connection fails, the error console will display a message: eMail servers use a default setting for DHE environments.
But we can't find where that setting is on our Smartermail server. Could anybody give me a hint?