Twitter and Yandex websites do not open at different times of the day. When they attempt to enter these sites, including administrators, they receive a "Cannot display page" error. Then the problem is resolved automatically and the sites are opened. I changed the DNS, but there was no solution.
I want your help in solving the problem.
Hi Mehmet K
Did you see anything in the Sophos Web Appliance reports? And were there many users facing the same problem at the same time or has this been isolated incidents?
All users with administrator privileges are having the same issue at the same time. Public users are already prohibited from accessing.
Do you see anything in the reports? For the Web Appliance, it would be better to create a case with Sophos Support as we can not take the backend access. Also, PM me the case number after you create it.