some days ago an user report a specifical issue to access to our wordpress site stored in an apache2.4 running on Ubuntu 12.04 LTS. If he try to access from the office, obtain a 403 error and the logs show "AH01630: client denied by server" but if try to access from another connection (other office, his home or any different of the office where work), can access without any problem.
We have published others 2 sites in the same server, all with the same vhost configuration (obviusly changing the ServerName and root Directory), and that 2 sites work perfectly from anywhere, including the office where cant access to the first site.
I disable fail2ban in the server, and confirm to IPV6 is disabled too. I dont have any .htaccess ban rule and the last server configuration changes was done 3 months ago, but this issue just have 3 days. I check all the logs and the previous logs (four days ago and before) report complete access to the site from the office where report the issue.
Thanks in advance for any sugestion to find the solution.
Regards.