GoDaddy was using what they refer to as "anti-phishing techniques" that was causing all sorts of email to be lost.
Something as simple as someone having their own domain (so their return address is 'mydomain.com') but they send through the SMTP server of their ISP. So the sending domain is not euql to the return domain. Dumped. No notice, no nothing. dumped.
Another example was placing a link to a web site in the body of a message. If the domain of that URL was different that the domain of the from address, dumped.
There were other instances I've forgotten about. I don't really care about it anymore as I'm no longer a customer of theirs. Their customer support was USELESS. It was constant finger pointing away from them. It wasn't until I got an officer of the company that I started getting solid answers. The end result was like something from Star Trek, and Mr. Spock. The needs of the many outweigh the needs of the few, or the one.
They were uninterested in the fact I was loosing mail. They felt they were "protecting me". I told them I was leaving as an unsatisfied customer. I voted with my feet.
I was not only loosing mail from list servers, I was occasionally loosing mail from eBay and Paypal that releated to my sales. Unacceptable.
I feel better too because I went from a plan that cost $25 a year to $12 a year at 1and1.com and I full control of the filtering. I have it all turned off and I no longer loose any mail.