Check config: auto forward to another user

[nyu]

Hi All,

I have an issue.
I have an account (A@a.com) when received email from outside (B@b.com) and email auto forword to (C@a.com) (just only receive from B@b.com)

I don't know how to check this config and remove it.
My server running OpenSource 7.2.1 version
Thanks for your help

[nyu]

Anyone help me advice??
Thanks a lots