Thanks for your reply. I was abled point to the mailman.cfg path appeared in mailman info. Below is the result of mailman conf. But archive is still now showing on web browser.
[archiver.hyperkitty] class: mailman_hyperkitty.Archiver [archiver.hyperkitty] clobber_date: maybe [archiver.hyperkitty] clobber_skew: 1d [archiver.hyperkitty] configuration: /etc/mailman3/mailman-hyperkitty.cfg [archiver.hyperkitty] enable: yes [archiver.mail_archive] class: mailman.archiving.mailarchive.MailArchive [archiver.mail_archive] clobber_date: maybe [archiver.mail_archive] clobber_skew: 1d [archiver.mail_archive] configuration: python:mailman.config.mail_archive [archiver.mail_archive] enable: no [archiver.mhonarc] class: mailman.archiving.mhonarc.MHonArc [archiver.mhonarc] clobber_date: maybe [archiver.mhonarc] clobber_skew: 1d [archiver.mhonarc] configuration: python:mailman.config.mhonarc [archiver.mhonarc] enable: no [archiver.prototype] class: mailman.archiving.prototype.Prototype [archiver.prototype] clobber_date: maybe [archiver.prototype] clobber_skew: 1d [archiver.prototype] configuration: changeme [archiver.prototype] enable: no
also from comment above my /opt/mailman/var/archives/hyperkitty/spool/ contains *.pck files.