[exim] Bad Header - Bad Form

Hi,

At my office we have a old exim running (4.63), I know we have to upgrade
it, but some time it's hard to make understand that in a office.

Actually one of our client can't send mail to one domaine name.

Our client mail all the time go in quarantine, the remote server return a
Bad Header - Bad Form error.

The remote server manager don't tell me more.

I check on our "friend" google without found a solution/discution about
that.

Any idear ?

Regards

Totoro