The first step in fixing the QuickBooks Multi-User Mode not working with H202 error is to verify your network settings, make sure you have steady internet access, and update QuickBooks. Use the QuickBooks File Doctor tool to conduct an analysis after configuring firewall and security tools to permit QuickBooks access. Call us at (855) 738-0359 to use the QuickBooks File Doctor tool or to chat with QuickBooks support.if any of those solutions fail to solve the issue.