Mail export

I've installed ispconfig on my server according to this guide:
https://www.howtoforge.com/tutorial/perfect-server-ubuntu-with-nginx-and-ispconfig-3/

It has worked well running my website and mails on it for a couple of months, until I had a problem with SSL, I tried some stuff and basically broke it after trying to update ISPConfig. I couldn't access my mails anymore getting an error config.inc.php couldn't be located. I changed permissions to the file to 644 like this: chmod 644 /etc/roundcube/config.inc.php

Now I just get a blank page when trying to access webmail. I can't access via imap either.
I can still access my vps via ispconfig panel and have ssh root access.

I am currently routing my mails elsewhere but I've got some important info in my mails that I would like to retrieve, is it possible to export my mails somehow? Or find a way to access them again?
I have very limited knowledge of linux and ISPconfig and should not have been using this for critical information with my limited knowledge, I am aware of that.

Edit:
/var/log/roundcube/error gives:

Expand: error log

$
[09-Jan-2018 08:57:51 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/zipdownload/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/?_$
[09-Jan-2018 08:57:51 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/jqueryui/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/?_tas$
[09-Jan-2018 08:57:52 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/zipdownload/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/?_$
[09-Jan-2018 08:57:52 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/zipdownload/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/?_$
[09-Jan-2018 08:57:56 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/zipdownload/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (POST /squirrelmail/?$
[09-Jan-2018 10:56:44 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/zipdownload/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/)
[09-Jan-2018 10:56:44 +0100]: <u69fdook> PHP Error: Failed to load config from /var/lib/roundcube/plugins/jqueryui/config.inc.php in /usr/share/roundcube/program/lib/Roundcube/rcube_plugin.php on line 157 (GET /squirrelmail/)

But I think that was before it stopped working.