One of my email providers had an expired certificate (I use Secure to Dedicated Port (TLS)). Now I get

The server didn't provide a root certificate during the session and there is no corresponding root certificate in your address book.

It's been a while since I did this, but I thought that TB automatically prompted for - and then imported - the certificate. Similar to Thunderbird. Do I need to do request my provider for their cert and manually import it into my address book?

Thanks.