[horde] Horde - Problem session timeout

[Jose Luis Marin Perez]

hi friend.. i have installed horde webmail v1.2.11.. everything works fine
except for when you compose an email, after a few minutes get the following
message: Please log in again to resume composing your message. If you are
NOT using cookies AND you are composing messages in popup windows, you will
have to log in again in your main window as well. 

This usually happens in particular with some users that are on a network
with enough restrictions, may perhaps be due to that? or believe that there
is another cause of this error?

Configuration:

Horde
$conf[session][timeout]=0

PHP
session.cookie_lifetime = 0


Please I need your help to solve this problem.

Thanks

Jose Luis