I don’t want to setup my own MX server, my domain mail (for a few family members) is currently been handled by a free DNS provider and a free email provider. I have no problem with those, and they are stable.
What I would really like is a gmail.com or outlook.com level of a web-based client, and have a copy of all of the email on our own server, and not have it remain on the mail host (even though they give it to me for free).
Also needs the ability to connect to multiple email servers, as some of my users use gmail, and others use yahoo and still other use outlook.com. And of course, some use multiple mailboxes.
I’m ok with running a VM, but would prefer a dockerized option.
Must be gratis, preferably open-source.
Since I’m expecting the mailboxes to be large, it will need to have good search capabilities.