OK, I turned on the password management interface from gnome-software,
and now syncing has partially worked. The Epiphany snap could sync
bookmarks and history, but not passwords from Firefox. I tried to log
into Outlook and Gmail but the Epiphany snap did not have the passwords
synced from Firefox
The snap has a password management interface but it's not autoconnected,
you should be able to enable it from gnome-software epiphany's detail
page (it has an interfaces button). Could you try if that makes it work
for you?
** Changed in: epiphany-browser (Ubuntu)
Importance: Undecided => Low