======== Required information ====
- iRedMail version (check /etc/iredmail-release): 0.9.7
- Linux/BSD distribution name and version: Debian
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

Hi, after updating iredmail/iredadmin to the latest versions a few days ago I am experiencing a problem that I don't know how to tackle.

Everything works fine after a fresh start of the server. After a few hours all web interfaces (roundcube, iredamin, sogo) stops responding (every browser returns a version of the message "cannot connect to the server").

# service nginx status
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled)
   Active: active (running) since Sun 2017-07-23 16:49:12 BST; 2h 56min ago
  Process: 346 ExecStart=/usr/sbin/nginx -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
  Process: 236 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=0/SUCCESS)
 Main PID: 459 (nginx)
   CGroup: /system.slice/nginx.service
           ├─459 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
           └─474 nginx: worker process

Jul 23 16:49:12 mail systemd[1]: Starting A high performance web server and a reverse proxy server...

SSH still works and 1 our of 3 times ActiveSync also works (most of the times it stops working as well).

I am not sure exactly what I should be looking at: I had a look at nginx logs, but couldn't see anything really weird... any suggestions?