Hi, I am facing a problem with exchange mail box creation for a user in our company. Actually, we have a datacenter with PDC (like PDC.abc.com) and Additional Domain Controller (like EXG.abc.com) with Enterprise exchange server 2003 installed in it. And I was installed a child domain (TEST0.test.abc.com) with windows 2003 server standard edition, exchange server 2003. Installation was successful and I didn?t get any error messages in installation log file. And replication is happening properly from child domain to PDC and child domain ADC and vise versa. Now, I am trying to create a user in child domain with exchange mailbox, but, I am getting a error message while assigning mailbox to user. "The server is not operational" "Facility: win32 "Id no: 8007203a" "Microsoft active directory-Exchange extension" I can able to create a user without mailbox for it. But I have to assign mailbox also for the users. What could be the problem it may.. Did anybody found this type of problem ever? If anybody knows solution for this pls reply me. Thank everybody, robin