As you can see in the picture below, icons do not show. They are missing on all pages, also on buttons. This does not change after emptying cache and rebuilding the menu. I've also checked the resource URL, and it seems to be correct. Do you have any idea, what might be the problem?
Thanks a lot in advance and best regards!!
Administer -> System setting -> Resource URL
andAdmin -> S/m setting -> Directories
and see if all of them are configured correctly