Long story short, a bunch of e-mail servers reject all e-mail originating from my server. Let's just say they're prejudiced against "small business" servers.

The new CathInfo software has plenty of features that require a VALID E-MAIL ADDRESS to take advantage of: 

* Topic notifications (when you subscribe to a topic, the system sends you an e-mail when someone else replies)
* Password reset
* E-mail from other members
* Happy Birthday e-mails from CathInfo
* etc.

But even if your e-mail is valid, if your e-mail ends with one of these domains, it will not work with CathInfo.
Gmail works great, and is totally free. I recommend getting a gmail account. 

SERVERS THAT BLOCK ALL E-MAILS FROM CATHINFO:
neo.rr.com
comcast.net
aol.com
sbcglobal.net
gmx.net
gmx.com
lycos.com
yahoo.co.uk
zoomtown.com
grandecom.net
netscape.net
shaw.ca
btinternet.com
rcn.com
wi.rr.com
netzero.com
mail.com
myself.com
twc.com
optonline.net
protonmail.com
sky.com

The above list is what I have so far -- but it's far from exhaustive. There are certainly others.