Hello everybody,

Sorry for this repost, but I'm stumped on this issue. 
First let me fill you in on my setup.
My server runs FreeBSD 9.2-RELEASE and provides the jail containing my web server that runs nginx 1.4.3. with php 5.5.5 along with php-fpm.
I am deploying Roundcube Version 0.9.5 (and Roundcube in general) for the first time and the installation process seemed smooth so far.
The Roundcube config generator / installer indicates that all requirements are met and testing the connection to my mailserver from there also worked, but now I’m getting the error mentioned in the subject line "Your session is invalid or expired”.
I tried several machines, different browsers and various operating systems. After activating the log files as suggested in an old thread I found upon researching the error, I got the following (anonymized) output:

logs/session:
[23-Nov-2013 15:49:56 +0100]: Session auth check failed for ; timeslot = 2013-11-23 15:45:00
[23-Nov-2013 15:49:56 +0100]: Session authentication failed for ; invalid auth cookie sent; timeslot = 2013-11-23 15:35:00

logs/sql:
[23-Nov-2013 15:49:56 +0100]: [1] SET NAMES 'utf8';
[23-Nov-2013 15:49:56 +0100]: [2] DELETE FROM session WHERE sess_id = 'c06f4*snip*a8d';
[23-Nov-2013 15:49:56 +0100]: [3] SELECT * FROM users WHERE mail_host = 'mx01.example.com' AND username = 'nonaya@example.com';
[23-Nov-2013 15:49:56 +0100]: [4] UPDATE users SET last_login = now() WHERE user_id = '1';
[23-Nov-2013 15:49:56 +0100]: [1] SET NAMES 'utf8';
[23-Nov-2013 15:49:56 +0100]: [2] SELECT * FROM users WHERE user_id = '1';
[23-Nov-2013 15:49:56 +0100]: [3] DELETE FROM session WHERE sess_id = '3a178*snip*9e3’;

logs/userlogins:
[23-Nov-2013 15:49:56 +0100]: Successful login fornonaya@example.com (ID: 1) from 17.*snip* in session 3a178*snip*9e3


Following another thread on this error, I checked the timezones / time + date settings of my host:

usr/local/etc/php.ini:
date.timezone = Europe/Berlin

date "+%Z” output from Host:
CET

date "+%Z” output from Jail:
CET

date "+%Z” output from OSX Client:
CET

I would very much appreciate your input on this problem!
Thank you very much,

Sincerely,
Sebastian