Install CSS/HTML problem

Community Server/Control Panel version: 11.5.4.1582
Type of installation of Workspace : deb
OS: Ubuntu
Browser version: Firefox

Hello,

I have just tried to install OnlyOffice on an Ubuntu server. The installation went fine apparently but when I log in to OnlyOffice, it seems that some CSS/HTML/ICONS are missing :

Does someone has had this problem ? A reboot didn’t change anything.

Thanks

Hello Swe.

Could you please clean browser cache\cookies (or check different browser)? Will it change the situation?
Also please point me to the guide which you used for installation and output result of df -h command from host.