Hi, We have Exchnage server 2003 with FE and clustered BE environment.We have multiple domains on our exchange.But one domain is not able to recive mails from any domain with ".XX" extension.The users of other domains are recieving the mails from all domain, only one domain has the problem.The sender from .xx doamainrecieves the following delivery error,sameers@xx.xx (5.1.1 unknown or illegal alias: sameers@xx.xx)I have checked all the setting and Receipent Polycies on our server but can't find any reason for this issue.Could some please help me in thie regard..ThanksAsif