[imp] Cannot send email

[Guillaume Chartrand]

Hi,

I know this question is already asked ans answered in the wiki but it's
doesn't solved my problem.
Here's my spec.
Horde 2.13
IMP 2.21

It's been working well for long time but now I cannot send mail thru the
Horde project and I don't know why. I restart my server and it's doesn't
help.
I can send email thru the command line with echo Test |
/usr/lib/sendmail guillaume.chartrand at collanaud.qc.ca 
In the php.ini the safe_mode is off and file_upload is on
In the imp/config directory I don't have the defaults.php3 who's
describes in the wiki. I create one with just <? $default->/usr/lib ?>
but it's doesn't work
In the horde/config/conf.php the path to the sendmail is good.

So What can I do.

Thank

----------------------------
Guillaume Chartrand