All recipients in distribution list not receiving messages


New Email
I've just joined a local gardening club and the moderator mentioned that when using BCC (he just started using this) not everyone is receiving his messages. He assumes because of using BCC the messages are going to junk mail. I have never had that problem. I asked a local PC friend and he said it is most likely junk mail, spam filter or firewall blocking on recipient's end. If this is true how can we overcome the problem. I believe he is sending to 100+ recipients.
Thanks, Char