[pure-ftpd] Unknown certificate

Hello List,

Connecting to pure-ftpd-1.0.49_1 with Filezilla shows the "Unknown
certificate" window, which shows the installed Comodo/Sectigo wildcard
cert.

No such problem happens when connecting with Thunderbird to Postfix or
Cyrus. The difference though is that there is a CA root/intermediate
certificate bundle installed in Postfix and Cyrus.

Is there a way to install CA root/intermediate certificate bundle in
Pure-FTPd?

If yes, will that preempt the "Unknown certificate" window in Filezilla
and other FTP clients?

-- 
Janos Dohanics