[imp] Login failure for one user

[Patrick Atlas]

One of our customers is trying to connect his webmail. But after
login/password he still get the login page.
In the log file, I see that he is logging the system, no error shown.

I can't get the same error when I use his login/password and, till now, he
is the only one with this problem.

He is using IE 6 last release. Our horde/imp installation is version 3. The
log system is using imap.

Is it a problem from his installation? Firewall, cache or something else? Or
from our horde installation?

Thanks for any idea.

Patrick Atlas