Millions of small compaines host their own email without issue. Of course reputation is a factor. Letting just anyone and where send email is why we have such huge spam problems and taking reputation in to account helps cut down on spam. I'm 100% sure this is a configuration issue and not Google and MS blocking out 'the little guy'.

I'm not sure that's quite true. As a technician for tmobile, I have been involved in setting up many tmobile hotspots and each one has been some sort of T1 connection to the site.