The web gui doesn't work after a system update

Hi everyone I have a issue with the Web GUI. After a update of the system (apt-get update && apt-get upgrade) the Web GUI has stop working. If I enter via Web Browser it doesn't show anything, the web is blank even via HTTP or HTTPS, and the Favicon Icon is displayed. I tried to restart NGINX, nothing, restart php5-fpm, nothing, restart the entire server, nothing, still the same. The other services work without problem, SSH, SMB and NFS Shares, the only problem is the Web Interface. The log of NGINX (/var/log/nginx/openmediavault-webgui_access.log and openmediavault-webgui_error.log) doesn't show any error. I also have used the command omv-firstaid without any result. I'll appreciate any help please .

My version of OMV is 2.1.27

Greetings and thanks

I tested in all browsers I have, Firefox, Chrome, IE and Edge, all the same, I cleared the cache in all browsers still the same. Besides I also tested in others machines at the same LAN and the problem persists.

Apache is not installed in the system, the web server is nginx.

root@cdf-nas:~# dpkg -l | grep apache
root@cdf-nas:~# dpkg -l | grep apache2
root@cdf-nas:~# dpkg -l | grep nginx
ii nginx 1.6.2-5~bpo70+1 all small, powerful, scalable web/proxy server
ii nginx-common 1.6.2-5~bpo70+1 all small, powerful, scalable web/proxy server - common files
ii nginx-full 1.6.2-5~bpo70+1 amd64 nginx web/proxy server (standard version)

And yes, I update the system via command line, because I found that I had an error in /etc/apt/sources.list with the line of debian-security repository.

hello again

Sorry but, this command doesn't exist in the system (omv-aptclean)

root@cdf-nasdmz:~# omv-
omv-config omv-initsystem omv-mkaptidx omv-mki18ndict omv-pm-standby omv-rmraid omv-sysinfo
omv-engined omv-jsminify omv-mkconf omv-mkraid omv-po2json omv-rpc omv-update
omv-firstaid omv-jsonprettify omv-mkgraph omv-mkwebjs omv-release-upgrade omv-run
root@cdf-nasdmz:~# omv-

I ran the others and the problems persists

Wow, I did not realize that I have configured debian backport repository maybe the problem is in the nginx package of backport repository. How I can downgrade to the nginx package of the main respository?

Thank very much for the help!!!!

I solved the problem, the problem was the nginx package from the backport repository installed after the system update.

This is what I did:
1- Delete the backport repository line from /etc/apt/sources.list
2- Run the command apt-get remove nginx (this also remove openmediavault's packages)
3- Run the command apt-get update to update de index without the backport repository
4- Run the command apt-get install nginx openmediavault

Great work with this software, keep going doing that.

Bye