mailx error message -- "me": not a group

Hi all,

When I tried to use mailx like mailx -s "test" someone@somedomain.com < myfile , mailx replies with "me": not a group. Mail did get sent though.

So how to deal with this "me": not a group response. I guess it is because some property was not set properly. Because mailx worked well before and after I run mkenv to reconfig my env. file(s), this error message popped up. But I am not sure which property was changed by mkenv.

Thanks!