From what I can gather, Kristi is that the board email addresses work just fine on my server. My reason for stating this is the fact that when I ask for the board to send me my lost registration info and password, it sends it just fine. From the same email address in the board software I am using.
If there was a problem on my server relaying emails from that defult board email address I have set up on my server, the password send feature surely would have given me the same error smtp 553. I will be in touch with my hosting company here shortly to have them look into the problem.
However, at this time I am to assume there is something wrong with my UBB software and I will need your help to get it back working properly as its my money that payed for it, or I will fight to get my money back and move on!
I will post updates soon as I get information from my hosting company.
