Recently, you getting error messages when attempting to open QuickBooks in multi-user mode. There can be several causes QB is not installed on the server, and hosting settings may not be configured properly. You need to try restarting your computer, run the QuickBooks File Doctor tool, and check host mode https://www.askforaccounting.com/quickbooks-multi-user-mode-not-working-2-easy-fixes-to-prevent-this-error/