I have a listserv and for years has been working fine.
Since last year people start complaining that most of their received messages from the list serv are been capture or not delivered by their spam filters.
Sometimes i have to call their ISP and tell them these are valid, clean messages and they edit their filters and problem fix.
But them after a while it happens again and again.
I am using L-soft, which is manage by another company, so the listserv is not host in house.
What can i do to fix this ?
How does spam / spam filters work?
Having my own hosted listserv will be a better option?