Network problems, improper hosting settings, or firewall restrictions could be the cause of your inability to Can’t Switch QuickBooks to Multi-User Mode.  In order to fix them, you must confirm user permissions, look up the location of corporate files, and make sure QuickBooks services are operating correctly.  Rapid, smooth multi-user access is restored through proper troubleshooting.  For professional QuickBooks help, give 1.855.738.2784 a call.