Finally, I decided to switch to a proper XMPP client Gajim, after I discovered mam, message carbons, client state indication, and stream manangement with the help of a friend. Because of the state of SSL CA bundle on FOSS operating systems, I’d to manually configure CA bundle on my
λ iconv -f iso-8859-1 -t utf-8 /usr/local/share/certs/ca-root-nss.crt >~/.local/share/gajim/cacerts.pem
After this connecting to the XMPP server worked as expected. This was needed as Gajim doesn’t know where CA certificate bundle is present on FreeBSD hosts, and on top of that CA bundle is
ISO-8859-1 encoded, whereas nbxmpp expects utf-8 encoded CA bundle. Also came to know support for CA path on FreeBSD has been added, but apparently not quite fixed, IMHO.