dear C5 team
a strange issue is happening at my client company is that the header is not appearing properly on all of client workstations,
when they enter the below link and put the username and password the header shows blanc
www/dietdelightscenter.com/index.php/login

any other places outside my client company is working fine,
tried from several internet source, different operating systems, different browsers and the header is appearing perfectly fine, only at my client company computers the header is showing as blanc!
we have contacted the ISP and they said that there is no issue from their side, also we have tried to access the CMS directly from the main router and the issue still persist,
i have tried even to change my hosting server to another registrar, the issue still showing,
also when login in using admin account it is still the same problem!
the link to access the CMS is:
www/dietdelightscenter.com/index.php/login

any help!