You get error when you click clock icon in File manager to change folder permission:

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.NullReferenceException: Object reference not set to an instance of an object. at WebsitePanel.EnterpriseServer.TaskManager.WriteLogRecord

Two common causes of the error are:

1. WebsitePanel on server is not installed correctly, either incorrect access password or mismatch WebsitePanel version on control/remote server.

2. Some website in user account has incorrect setting. Website has incorrect web.config file, missing home folder, website left over on server but no record in WebsitePanel.

Go through all possible issues above and fix when found then functionality of file manager will be restored.