Excel file

Hi people, There has been a problem with one of the excel file in a shared folder hosted on a server connected to our LAN. Normally every dept could open up the file but now only 1 dept could open the file. The rest of the company wasn’t able to open it just hang there when you open it. I have check the permissions on the file and the server everything is alright. Anyone encounter this problem before? Do help thanks been bugging me for 2 days.