Why Is QuickBooks Multi-User Mode Not Working?

https://quickbookhelpdesk.com/blog/fix-quickbooks-multi-user-mode-not-working/

QuickBooks Multi-User Mode may stop working because of incorrect hosting settings, network problems, firewall restrictions, QuickBooks services, or Database Server Manager issues. Start by checking that only the correct server is hosting the company file. Then run a scan with QuickBooks Database Server Manager and make sure the required QuickBooks service is running. Check the network connection and firewall settings as well.