I have a problem with several Concrete5 websites. All are running 5.7.5.9, on Apache server with php 5.4.45.
Navigation on the website is without problem, editing the website has no problem, but when I access the sitemap page in the dashboard I got the attached screen. After a refresh of the page it load just fine.
Other dashboard pages also works fine, except the Clear cache page where i got the same issue after hitting the Clear cache button. The cache are disabled on the website since it is in development.
Tried to solve the issue with the server admin but they don;t have any clue about it.
Also I would like to mention I'm running Win 10 and have the issue in Chrome and Firefox, but not in Edge.
Any help? Is it a server problem, is it something locally (however I have the same problem at the office and at home either).

Thanks.