We changed our server from outlook 2007 to outlook small business server 2008. since then i can not validate my e-mail and the password is correct. can anyone help me with this?

BES or BIS? If BES, check with your Admin. Presuming BIS, is your new email server fully functional from outside the firewall? For instance, can you access webmail from the road or set up a POP3 using a third party app? Did your URL change?

-jk