Mail routing issue after to Lotus 7.0.3 on AIx , please help

Two days before we upgrade our lotus domino server from R 5.0.11 to 7.0.3 in AIX server , after no mails are routing to

this server even internally ,

it bounce back with below error

No route found to server XXXXX/O from server XXXX/O. Check Server and Connection documents in the Domino Directory.